PLANTS,SEEDS 
AND CURRENTS 

IN THE 
WEST INDIES 
ANDAZ.ORES 

H. B:GUPPY 



i 



PLANTS, SEEDS, AND CURRENTS IN 
THE WEST INDIES AND AZORES 



PLANTS, SEEDS, AND 
CURRENTS IN THE 
WEST INDIES AND 
AZORES 

THE RESULTS OF INVESTIGATIONS CARRIED 
OUT IN THOSE REGIONS BETWEEN 1906 
AND 1914 



BY 

H. B. GUPPY, M.B., F.R.S.E. 



WITH THREE MAPS AND A FRONTISPIECE 



LONDON 
WILLIAMS AND NORGATE 

14 HENRIETTA STREET, COVENT GARDEN, W.C. 

1917 



Printed in Great Britain by 
Richard Clay & Sons, Limited, 
brunswick st., stamford st., s.e., 
and bungay, suffolk. 



PREFACE 



With the exception of the section on the Azores, this work 
was practically completed before the war began; and it is now 
presented very much as it was written in the pre-war period. Un- 
fortunately I greatly under-rated the task involved in the pro- 
duction of the fair copy; and for this reason, as well as through 
sickness and other causes, there has been considerable delay in its 
preparation for the press. 

Associated with my observations on seeds and fruits, the results 
of which were published in 1912 under the title of Studies in Seeds 
and Fruits, the work embodied in these pages represents about 
ten years of my life. The two winters of 1906-8 were spent in 
Jamaica, that of 1908-9 mainly in Grenada but also in Tobago 
and Trinidad, and that of 1910-11 in the Turks Islands. Subse- 
quently two sojourns were made in the Azores, the first from the 
middle of February to the end of April 1913, and the second from 
the middle of June to the middle of August 1914. 

The great lesson that I have learned from the numerous difficult 
distribution-problems presented in the West Indian region, is that 
one can no longer fight shy of accepting in principle the conclusions 
relating to past changes in the arrangement of land and water in 
the Caribbean area, which have long been formulated by English 
and American geologists and zoologists. The witness of the living 
plant is often quite as insistent as the testimony of the rocks. Yet, 
although the original holders of such views stood more or less alone 
in their advocacy of them forty or fifty years ago, some of them, 
like Mr. Lechmere Guppy, who died recently at Port-of- Spain, 
lived to see their final justification. 

The inclusion of the Azores within my field of investigation 
arose from a desire to come in contact with some of the problems 
presented by the floras of the Atlantic Islands. In the previous 
decade, 1896-1906, I had been brought face to face with problems 
offered by the islands of the Pacific. Polynesia and the history 
of its plant-stocking had occupied much of my thoughts during a 
long period, and I turned to Macaronesia with the hope that as 
typified in the Azores this region might bring me once again under 
the spell cast by the problems of oceanic distribution. Yet the 
outlook was at first far from encouraging, and it was suggested to 
me that it was scarcely worth while to take up the study of islands, 
concerning which we had long known all that was worth knowing. 
However, a re-perusal of Hooker's famous lecture on insular floras 
whetted my curiosity, and I soon found that the Macaronesian 



vi 



PREFACE 



islands were rich in distribution-problems almost as fascinating as 
those presented by Hawaii and other Polynesian groups. 

Yet but few of these problems were directly indicated in the 
catalogues of the floras accessible to me ; and I realised here, as I 
did in the Pacific, that the work of the systematist in framing a 
catalogue of a flora represents the means to an end and not the 
end itself. In other words, with a list of a flora in our hands we 
stand only at the threshold of the study of distribution. Here 
also I realised that there is no region so well known that it would 
not greatly benefit by a thorough overhaul of all the data from a 
generally accepted standpoint of distribution; and the conviction 
forced itself upon me that the student of distribution will find his 
task nearest-at-hand, not in the discovery of new facts, but in the 
elaboration of old ones, and in the adoption of a uniform method 
of treatment. The elimination of the introduced plant should be 
the first goal of the student of distribution. Yet it is not possible 
for him to procure intelligible results, since he employs one method 
for the British Islands, another for the Azores, another for New 
Zealand, and a fourth for the Hawaiian Islands. The story of the 
weed all over the globe is full of significance, but only for the student 
of the early history of man. 

H. B. Guppy. 

"Bosario" Salcombe, 
South Devon. 

Nov. 23, 1916. 



LIST OF SOME BOTANICAL AND OTHER 
WORKS QUOTED IN THESE PAGES IN CON- 
NECTION WITH DISTRIBUTION IN THE 
WEST INDIAN REGION AND ELSEWHERE 

(Other lists dealing with special subjects are given at the end 
of chaps, ii, iii, xi, xiii, xv, xix.) 

Catesby, M., Natural History of Carolina, Florida, and the 

Bahamas; i. 1731; ii. 1743. 
Ernst, A., The New Flora of the Volcanic Island of Krakatau, trans. 

by A. C. Seward, Cambridge, 1908. 

p^^^A^B jFlora of Jamaica, vol. iii. 1914. 

Grisebach, A. H. R.. Flora of the British West Indian Islands, 
1864. 

Guppy, H. B., Dispersal of Plants as illustrated by the Flora of Keeling 
Atoll, Journal of the Victoria Institute, London, 1889. 

Plant-Dispersal, 1906 (vol. ii. of Observations of a Naturalist 
in the Pacific). 

Plant-Distribution from an Old Standpoint, Trans. Vict. Inst., 
London, 1907. 

Distribution of Plants and Animals, Petermann's Mitteilungen, 
1910, heft 2. 

Studies in Seeds and Fruits, 1912. 
Harshberger, J. W., Phytogeographic Survey of North America 
(Engler and Drude's Die Vegetation der Erde, vol. xiii. Leipzig 
and New York, 1911). 

The Vegetation of South Florida, Trans. Wagner Free Institute 
of Science of Philadelphia, 1914. 
Hart, J. H., Herbarium list, Botanical Department, Trinidad, 1908. 
Hemsley, W. B., Reports on the Scientific Results of the Voyage of 
H.M.S. Challenger, Botany, vol. i. 1885 (reference to this work 
is often abbreviated to Chall. Bot.). 
Hooker, W. J., The Niger Flora, 1849, including sections by G. 

Bentham, J. D. Hooker, and others. 
Millspaugh, C. F., Plantae Utowanae, 1900 (plants collected in the 
Antillean cruise of the yacht Utowana). 
Plantse Yucatanae, 1903-4. 
Flora of the Sand-keys of Florida, 1907. 
Praenunciae Bahamenses, 1906-9. 

(All publications of the Field Columbian Museum, Chicago.) 

vii 



viii LIST OF SOME BOTANICAL AND OTHER WORKS 



S afford, W. E., Classification of the genus Annona, Contributions 
from the United States National Herbarium, vol. 18; Smith- 
sonian Institution, Washington, 1914. 

(Numerous botanical papers by this author, which are of 
great importance both to the botanist and to the student of the 
races of man in the tropics of the New World, have appeared 
in the last few years in the Journal of the Washington Academy 
of Sciences, 1912-15; in the Volta Review, Washington, 1912; 
in the Bulletin of the Torrey Botanical Club, 1912 ; in the Journal 
of Heredity, Washington, 1915; and in the Smithsonian series 
of publications above named.) 

Scharff, R. F., Distribution and Origin of Life in America, London, 
1911. 

Schimper, A. F. W., Die Indo-Malayische Strandflora, Jena, 1891. 

Spruce, R., Notes of a Botanist on the Amazon and Andes, 1908 
(edited by A. R. Wallace). 

Urban, I., Symbols Antillanse, vol. i. 1898-1900; ii. 1900-1901; 
iii. 1901-1903; iv. 1903-1911, Leipzig. 



CONTENTS 



CHAP. PAGE 

I WEST INDIAN BEACH-DRIFT 1 

II WEST INDIAN DRIFT ON EUROPEAN SHORES ... 20 

III THE CURRENTS OF THE ATLANTIC AND THE TRACKS 

OF DRIFTING SEEDS AS ILLUSTRATED BY BOTTLE- 
DRIFT 46 

IV THE SIMILARITY BETWEEN THE WEST INDIAN AND 

WEST AFRICAN LITTORAL FLORAS AS EXPLAINED 

BY CURRENTS 83 

V RHIZOPHORA MANGLE AND THE PLANTS OF THE GREAT 

MORASS OF THE BLACK RIVER DISTRICT IN JAMAICA 96 

VI THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS . Ill 

VII THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS 

(continued) 138 

VIII MISCELLANEOUS PLANTS 166 

ix miscellaneous plants (continued) .... 197 

x miscellaneous plants (continued) .... 225 

XI THE GENERAL CHARACTERS AND GEOLOGICAL STRUC- 
TURE OF THE TURKS ISLANDS 254 

XII THE FLORA OF THE TURKS ISLANDS .... 277 

XIII THE CURRENT-CONNECTIONS IN THE SOUTHERN HEMI- 

SPHERE 294 

XIV DIFFERENTIATION 313 

XV DISTRIBUTION 323 

XVI THE INFLUENCE OF THE DIVERGENCE OF THE CON- 
TINENTS ON THE DISTRIBUTION OF SPHAGNUM AND 

CAREX 332 

XVII THE AZORES 359 

xviii the Azores (continued) 389 

xix the Azores (continued) 417 

APPENDIX 441 

INDEX . . 505 

ix 



MAPS AND ILLUSTRATIONS 



WEST INDIAN SEEDS AND FRUITS REPRESENTED IN EUROPEAN 

beach-drift Frontispiece 

the ocean currents To face page 46 

THE TURKS ISLANDS . „ „ 254 

THE ISLAND OF PICO, AZORES .....„„ 359 



xi 



PLANTS, SEEDS, AND CURRENTS IN 
THE WEST INDIES AND AZORES 



CHAPTER I 

WEST INDIAN BEACH-DRIFT 

The study of the stranded seed and fruit-drift of the West Indian 
region, as in the case of my previous investigations in the Pacific 
Islands, offered a means of approaching the great problems of plant 
distribution. The inquiry was extended over four winters (1906- 
1911), and was principally carried out in Jamaica, the Turks Islands, 
Trinidad, Tobago, and Grenada. The last winter was spent in the 
Turks Islands with the object of studying the seed-drift most fitted 
for the traverse across the North Atlantic in the Gulf Stream, since 
in those small islands one is able to discriminate with confidence 
between the drift of local Origin and that brought from outside 
regions by the currents. 

Generally speaking, the drift has much the same character over 
all this region, except perhaps in Trinidad and the adjacent island 
of Tobago, where there is added a quantity of strange seeds and fruits 
brought by the Equatorial Current from the Amazon and the Orinoco 
and from the estuaries and shores of the Guianas and Brazil. It 
is also highly probable, as is shown in the discussion of the bottle- 
drift data in a later chapter, that West African seed-drift is trans- 
ported by the same current to the West Indies ; but there are obvious 
difficulties in the way of recognising it, since most of the littoral 
plants that constitute the principal sources of the drift are common 
to both sides of the tropical Atlantic. 

Its Sources. — The seeds and fruits found in the floating drift of 
these seas are derived partly from plants growing on the beaches, 
partly from plants of the n angrove swamps, and partly from inland 
plants growing on river-banks and on the slopes above. They are 
to be found in quantities on the beaches, especially in the vicinity 
of estuaries. But the scanty materials stranded on the coasts of 
Europe, as described in Chapter II., are but the residue of a vast 
amount of vegetable debris brought down by rivers to the coast 
and washed off the beaches by the currents. By far the greater 
mass of these materials must soon find a resting-place amongst the 
deposits at the bottom of the sea in the vicinity of their source. 

B 



2 PLANTS, SEEDS, AND CURRENTS 



The Sifting Process. — This sifting out of the less buoyant 
materials is well illustrated when we compare the vegetable drift 
thrown up on the small islands of the Turks Group with that deposited 
on the beaches of the larger islands in the neighbourhood of estuaries, 
as in the case of the Orinoco drift piled up on the south side of Trinidad, 
or, to take a less conspicuous example, of the drift stranded on the 
south coast of Jamaica in the vicinity of the Black River. These 
matters will be mentioned in a later page; but here it may be said 
that the foreign drift, which makes up nearly all of the larger materials 
stranded on the Turks Islands, presents us with the seeds and fruits 
that are most likely to be carried in the Gulf Stream across the 
Atlantic. The beach-drift of this small group displays the West 
Indian drift in transit at an early stage of the North Atlantic traverse. 

If we desired to know what seeds and fruits of the floating drift 
of the West Indian seas we ought to find on the shores of Europe, 
we must look for them, not on the beaches of the larger islands where 
they would be mixed with and sometimes lost among a mass of 
vegetable materials of local origin, but on the coast of some low, 
scantily vegetated, outlying islet standing well removed from the main 
islands. Such an islet would receive on its beaches a sample of the 
drift after it has lost all the less buoyant constituents during a 
flotation of some weeks in the open ocean. These are just the oppor- 
tunities which are offered in the several small islands and islets of 
the Turks Group. Here in sample we see the oceanic drift that is 
carried swiftly by the Gulf Stream through the Florida Channel and 
then past Cape Hatteras eastward to the shores of Europe. 

General Description of Drift. — With this object in view I will 
at first generally describe West Indian beach-drift, referring in passing 
to some of its special characters in particular localities. 

In the West Indies, as elsewhere, the local drift is generally pre- 
dominant, that is to say, the drift derived from plants growing in the 
vicinity, whether at the border of the beaches, or in the coastal and 
estuarine mangrove swamps, or in the interior along the sides of 
rivers. It is from the beaches near a large estuary that we can 
form the best idea of the nature of the materials that any particular 
region supplies to the currents for oceanic transport. If we confined 
our attention entirely to the drift brought down by rivers, or to the 
materials supplied by shore vegetation, our conception of its general 
composition would be incomplete. It is on a beach near an estuary, 
where the seeds and fruits derived from the beach plants are mingled ' 
with those from the mangrove vegetation and from the riverside 
plants of the interior, that we can learn our lesson concerning local 
drift. 

Yet this would take no cognisance of the foreign drift, the materials 
brought from a distance, often from a continental coast or from some 
island hundreds of miles away. This is liable to be masked by the 
local drift on a beach near an estuary. It is best sought for and 
most easily recognised on some long stretch of beach far from an 
estuary, since it is often not difficult there to differentiate between 
it and the drift supplied by the beach vegetation. But here again 
obstacles may arise. Some knowledge of the flora must be acquired, 



WEST INDIAN BEACH-DRIFT 



3 



and in a large island like Jamaica this is not a light undertaking. 
Even with Grisebacfrs Flora of the British West Indian Islands at my 
disposal, a work that bears especially on Jamaican plants, it was 
not possible to say with certainty that three of the most interesting 
plants represented in Jamaican beach-drift, Carapa guianensis, 
Manicaria saccifera, and Sacoglottis amazonica, though not accredited 
to the island, did not still survive in some of its extensive coastal 
swamps. It will, however, be subsequently shown that in the light 
of more recent investigations the probability of their not existing 
there is very great. 

These are difficulties likely to crop up in the case of all large 
tropical islands. Yet the incrusting cirripedes, Serpulce, and other 
organisms will frequently aid us in determining whether any par- 
ticular fruit or seed is from beyond the sea. It is only the outlying 
sand-key, such as occurs in the Turks Islands, that affords the 
opportunity of safely differentiating the foreign drift on a beach. 
Here after a few weeks spent in examining the local flora there is 
little or no trouble in making the discrimination. 

The riverside vegetation above the mangroves, the mangrove 
formation of the estuary and of the coast swamp, the plants of the 
beach and its border, all contribute to the floating drift of these seas. 

River-drift above the Mangroves. — A good deal of the materials 
brought down by the river, and I have in this sketch the Black River 
of Jamaica chiefly in my mind, consists of aquatic plants, such as 
Pontederias and Pistias, and of foliage, portions of tree-branches, 
etc., which do not count in distribution, and in the case of the floating 
plants are soon destroyed by the salt water or dry up when stranded 
on the beaches. These aquatic plants form a special feature of the 
floating drift of rivers of tropical America, and I have referred to 
them in the instance of the Guayas River in Ecuador in my book on 
Plant Dispersal (p. 488). Yet the plants of the riverside and of the 
wooded slopes of the river-valley above the mangrove-bordered 
estuary add a great variety of fruits and seeds to the drift floating 
in the stream, as illustrated in the description of the Black River 
given near the close of this chapter. 

Many of these floating fruits and seeds have little or no effective 
value for distribution except along the same river-system. Thus in 
the Black River drift occur in numbers the germinating fruits of 
Grias cauli 'flora, the germinating seeds of Symphonia globulifera, of 
Crinnm. and of Crudya spicata ; and one may add the seeds of 
Fevillea cordifolia, which even when they escape the fate of germina- 
tion in the river-drift are far from suited for dispersal over the sea. 
It is of importance to remember that through this tendency to germin- 
ate when afloat many of the seeds and fruits of the drift of tropical 
rivers are rendered useless for purposes of dispersal even across 
narrow tracts of sea. 

But amongst the fruits and seeds found afloat in West Indian 
river-drift, excluding those supplied by the mangroves and their 
associates, many others have no effective value for purposes of dis- 
tribution. Although the gourds of Crescentia trees and the fruits 
of Acrocomia palms are characteristic of this floating drift, the first 



4 PLANTS, SEEDS, AND CURRENTS 



named carry seeds that have a fleeting vitality and the second float 
only for a few days. Acrocomia fruits, it is true, are represented in 
the drift of the Turks Islands, but merely in the form of the empty 
44 stones," which, after being freed by the decay of the outer coverings 
of the stranded fruit, acquire buoyancy only through the loss of the 
seed. Then again both Andira inermis, a tree of the riverside, and 
Mammea americana, a tree of the forested slopes of the river- valley, 
add their fruits as a rule to the floating drift ; but it is very doubtful 
whether their seeds would be fit for germination when the fruits are 
stranded on some distant island. 

The fruits and seeds carried down by a West Indian river from 
the interior to the sea that would be fitted for crossing unharmed a 
broad tract of ocean are comparatively few. Taking all the kinds of 
seeds and fruits brought down to the sea by the Black River from its 
basin above the mangroves, I don't suppose that twenty per cent, 
would be capable of reproducing the plant after a traverse of a 
hundred miles of ocean. The seeds which are brought down by a 
Jamaican river from the interior to the coast in a sound condition 
and capable of sustaining without injury the effects of prolonged 
flotation in the sea, would include such leguminous seeds as those of 
Entada scandens, Mucuna urens, and Dioclea reflexa, all of which 
figure in the West Indian drift stranded in a sound condition on the 
shores of Europe. Then there would be the 44 stones " of Spondias 
lutea and the long pods of Cassia grandis, which, after they have been 
transported by the rivers to the sea, would still be able to carry some 
of their seeds unharmed far across the ocean. 

Drift supplied by the Mangrove Formation. — We come now 
to the vegetation of the mangrove formation as a source of the floating 
drift of West Indian seas. We have to distinguish here between 
the true mangroves and their associates. Together they form colonies 
everywhere, whether on the surface of some newly raised islet or 
key, or on the coast, or in the estuaries of the larger islands. Rhizo- 
phora mangle, Laguncularia racemosa, and Avicennia nitida are the 
mangrove trees proper ; and one of their most prominent character- 
istics is their viviparous habit, which, however, is less pronounced with 
Laguncularia than with the others. The occasional associates of 
the mangroves in the larger islands are Anona palustris and Carapa 
guianensis. In Trinidad we find also Manicaria saccifera and Saco- 
glottis amazonica together with a species of Bactris, a palm that grows 
in similar situations. The Manicaria and Sacoglottis trees are con- 
spicuous constituents of the estuarine floras of the great rivers of 
Venezuela, the Guianas, and Brazil. Though they only just enter 
the West Indian region, their fruits are distributed by the currents 
far and wide over the Caribbean Sea. 

All the above-named trees of the mangrove swamps contribute 
to the floating drift of these seas, the true mangroves being repre- 
sented in the case of Rhizophora by long seedlings, in the case of 
Avicennia by the germinating fruits and seedlings, and in that of 
Laguncularia by the fruits, which are often in the germinating con- 
dition. Uninjured by flotation in sea- water these seedlings and 
germinating fruits are cast ashore, and very soon establish themselves. 



WEST INDIAN BEACH-DRIFT 



5 



On the other hand, with the associates of the mangroves the floating 
fruit or seed has many difficulties to contend with that considerably 
restrict its capacities for distribution. Thus the seeds of Anona 
palustris and of Carapa guianensis are very apt to germinate when 
afloat in river-drift ; and my observations indicate that the germinat- 
ing seed would soon be killed when it reached the sea-water, though 
the dead seed might float a long time and be thrown up in a more 
or less empty or unsound condition on some distant shore. So again 
with Manicaria saccifera, the seeds do not seem to be able to with- 
stand sea- water immersion for a long period, though the fruit with a 
decaying or dead seed may be transported by the currents for a great 
distance. Sacoglottis amazonica is rather better adapted in these 
respects, 

Drift supplied by the Plants of the Beach and its Borders. — 
In the last place we will deal with the plants of the beach and its 
borders that add their buoyant seeds and fruits to the drift of the West 
Indian seas. Those which are most generally distributed, being 
those which are most characteristic of the drift, are enumerated below. 
In point of size the drift derived from beach plants in the West 
Indies offers a great contrast to that supplied by the beach vegetation 
of the tropical islands of the Indian and Pacific oceans. In the West 
Indies we miss the large fruits of Barringtonia speciosa, Cerbera cdol- 
lam, Ochrosia parri flora, Heritiera littoralis, Cycas circinalis, Pandanus, 
etc., trees that give character to the vegetation of the beaches of 
many an island and many a tract of continental coast in those oceans. 
The largest fruits of the common West Indian beach-drift, such as 
those of the Manchineel (Hippomane mancinella), Thespesia popv.lnea, 
and Ecastaphyllum brozvnei, are not more than lj inches (37 mm.) 
across ; and most of the other plants contribute seeds and seed-like 
fruits varying from a sixth to three-quarters of an inch (4-18 mm.) 
in size. 

The Beach Plants commonly represented in the Floating 
and Beach Drift of the West Indies. 

(One or two of the plants, like Conocarpus erectus, are perhaps most 
characteristic of the borders of the mangrove swamps, but since they 
thrive also amongst the vegetation bordering the beach they are here 
included.) 

Canavalia obtusifolia (seeds). 
Chrysobalanas icaco (stones). 
Coccoloba uvifera (stone-like fruits). 
Colubrina asiatica (seeds). 
Conocarpus erectus (achenes). 
Ecastaphyllum brownei (legumes). 
Guilandina bonducella (seeds). 
Hibiscus tiliaceus (seeds). 
Hippomane mancinella (stones). 
Tpomoea pes-caprce (seeds). 
Scoeiola plumieri (stones). 



6 PLANTS, SEEDS, AND CURRENTS 



Sophora tomentosa (seeds). 

Suriana maritima (seed-like nucules). 

Thespesia populnea (seeds liberated by the decaying fruit). 
Tournefortia gnaphalodes (pyrenes). 
Vigna luteola (seeds). 

There are one or two trees typically represented in West Indian 
beach-drift which ought to be mentioned, their fruits being carried 
long distances by the currents, such as Terminalia katappa and Cassia 
fistula. Both have been introduced from the Old World. The last 
named is discussed at length on a later page. The first is dealt with 
in my book on Plant Dispersal. It is a typical littoral tree of the 
tropics in the eastern hemisphere ; and in the West Indies it is tend- 
ing to escape from cultivation to find a home on the beach. 

Cirripedes, Serpulce, and similar organisms, that have attached 
themselves to floating drift, often enable one to distinguish the larger 
seeds that have been brought from a distance before being stranded. 
Where the plants concerned grow in the neighbourhood it is not easy, 
as before remarked, to discriminate between the foreign drift and the 
drift of local origin. The difficulties are well exhibited in an island 
like Jamaica. The large seeds of Entada scandens are common on 
the beaches of the north coast; but the plant grows in the island, 
and one cannot in the absence of incrusting shells of marine organ- 
isms determine whether a weather-beaten seed lying on the beach 
came originally from some neighbouring coast, such as from Cuba, 
or whether it has acquired its weathered appearance from lying 
exposed for a long period on the shore. On the other hand, the fruits 
of Manicaria saccifera and Sacoglottis amazonica would be rightly 
regarded as of foreign origin, since there is little probability of the 
plants growing in the island. 

The Sorting Influence of the Waves. — The waves often sort 
out the finer beach-drift, and deposit it in a line above the larger and 
heavier fruits and seeds which are usually mixed up with Sargasso 
weed, drift-wood, and similar materials. Small pumice pebbles and 
Spirula shells mark the line of deposition of the smaller seeds and 
fruits belonging to such plants as Hibiscus tiliaceus, Ipomcea pes- 
caproB, Suriana maritima, Tournefortia gnaphalodes, Vigna luteola, 
etc. It is, however, the larger drift that usually claims attention, 
the smaller materials being often overlooked. 

From my observations at St. Croix, Turks Islands, Grenada, 
Tobago, Trinidad, Jamaica, and Colon, it is evident that the beach- 
drift displays much the same general characters over the West Indian 
region. At the same time in addition to the seeds and fruits that 
are found on most of the coasts, whether insular or continental, each 
locality often presents some peculiar feature. Thus on the Colon 
side of the Panama Isthmus there are to be found on the beaches the 
large fruits of Prioria copaifera and empty palm fruits of Astrocaryum, 
etc. In Jamaica we find the fruits of Grias cauliflora ; and in Trinidad 
the ordinary seeds and fruits of the drift are often masked by the 
large amount of strange fruits and seeds brought down by the Orinoco 
and stranded on its south coast. 



WEST INDIAN BEACH-DRIFT 



7 



Method of Identifying the Constituents of the Drift. — My 
previous experience of the seed-drift of the islands of the Pacific and 
more especially of the American borders of the ocean, as in Ecuador 
and at Panama, had made me familiar with many of the constituents 
of West Indian drift. On the other hand, my later West Indian 
experiences helped me to identify constituents in the drift on the 
Pacific coasts that I had not before recognised. The method em- 
ployed was to search for the parent plant. In some cases a long 
time passed, as in that of Dioclea reflexa, before success crowned my 
efforts. This plant is of particular interest, as it is one of the few 
possessing seeds that are transported by the Gulf Stream in a sound 
condition to the shores of Europe. Ultimately I tracked it to one of 
its homes in the mountains of Grenada, and one of my chief objects 
of making a sojourn of some weeks in that locality was to investigate 
the conditions that led to its supplying its seeds to the drift. 

The same plan was followed in Jamaica whenever I came upon 
some new seed or fruit on the beaches. With the aid of my coloured 
companions, who were very zealous in helping me to find its source, 
it was often not very difficult. Thus it was not long before I found 
the parent plants of the Anchovy tree (Grias cauliflora) and of the 
large seeds of the Antidote Vine (Fevillea cordifolia) so common on 
beaches in the Black River district. 

Certain seeds and fruits common in the Jamaican drift eluded 
my efforts in this direction, and usually because the plants did not 
grow in the island. Two conspicuous offenders in this way were the 
fruits of Sacoglottis amazonica and Manicaria saccifera, two of the 
most interesting components of West Indian beach-drift. However, 
I was introduced to them by the late Mr. Hart of Trinidad. The 
source of the fruits of the first named was for a long time unknown, 
and Mr. Hart played a prominent part in the inquiry that led to their 
identification. Though not Jamaican, both are included in the 
Trinidad flora, growing mostly as I learnt in the swamps on the 
south side of the island. But as found on the Trinidad beaches the 
fruits often display evidence of long flotation in the sea in the marine 
organisms incrusting them. They have their chief home in the swamps 
of the Amazon and the Orinoco, and many of the fruits found in the 
Trinidad and Tobago beach-drift are doubtless thence derived. 
It was the presence of these fruits of Manicaria and Sacoglottis on the 
beaches of the south coast of Jamaica that long ago led Sir D. Morris 
to recognise an element of drift hailing from the Orinoco and the 
Amazon, a subject dealt with in connection with Jamaican beach- 
drift in a later page. 

Orinoco and Amazon Drift distributed over the West 
Indian Region. — " Orinoco drift " is a term often on the lips of 
residents in Trinidad, Tobago, and Grenada. They apply it to all 
the drift brought by the Equatorial Current, much of which must 
come from the Amazon as well as from the shores of Brazil and of the 
Guianas. Most of this drift finds its way into the Caribbean Sea 
between Barbados and the Spanish Main, either entering the Gulf 
of Paria and emerging through the Bocas, or floating through the 
passages separating Trinidad, Tobago, and Grenada. As indicated 



8 PLANTS, SEEDS, AND CURRENTS 



by the bottle-drift data, to be dealt with in a later chapter, most of 
the vegetable drift carried by this current would be borne across the 
Caribbean Sea in the direction of the coasts of Honduras. The 
materials that escaped being stranded on the shores of Central 
America or on the south coast of Jamaica, on the Cayman Islands, 
and on the south-west shores of Cuba, would be carried through the 
Straits of Yucatan into the Gulf of Mexico, some portion being 
beached on the shores of that gulf, the remainder ultimately reaching 
the Straits of Florida. 

Reference will subsequently be made to several bottles that have 
accomplished this passage in part, and to others that have done so 
in its entirety. Occasionally one of them stranded on the beach tells 
the story of the seed-drift lying around it. Thus, a bottle from Ceara 
on the north coast of Brazil, which Mr. Savage English mentions as 
cast up on Grand Cayman, clearly demonstrates the part played 
by the Equatorial Current in carrying drift to the Cayman Islands. 
" The quantity of living seed afloat at this western end of the Carib- 
bean Sea " (thus he writes in the Kew Bulletin, 1913) " must be 
immense, for it is hardly possible to examine more than a few feet of 
the windward beaches of Grand Cayman without finding a seed of 
some sort ; leguminous, probably, if it is not one from a Manicaria 
palm, though there are plenty of others." 

The Mode of Distribution of Orinoco and Amazon Drift. — 
Although the main track of the Orinoco and Amazon drift is chiefly 
restricted to the southern part of the West Indian region, any differ- 
entiation that the Equatorial Current might effect in the distribution 
of littoral plants, as it pursues its westerly course across the Caribbean 
Sea, would be obliterated by time. The usual variation of the winds 
between north-east and south-east would often bring about the 
deflection of the floating drift ; and we get cases like that of Jamaica, 
which receives some of the drift brought by the Equatorial Current 
on its southern shores and a quantity of Cuban and Haitian drift 
on its northern coasts during the prevalent north-easterly winds. 
Over most of the West Indian region outside the direct influence of 
the Equatorial Current there is a prevailing north-westerly and 
westerly set of the surface waters ; and it is in this manner that the 
beaches of the Turks Islands are often piled up with drift from San 
Domingo, Porto Rico, and the Leeward Islands. 

The Turks Islands and their Suitability for the Study of 
Seed-drift. — Though the prevailing winds in the Turks Islands are 
easterly, north-westerly winds occur at times in the winter months 
when different climatic conditions reign and the routine of the year 
is reversed for man, beast, and plant. The lee or protected sides of 
the islands for the greater portion of the twelve months now become 
the weather sides. At such times, when the sea breaks heavily on 
the shores, steamers cannot land either passengers or cargo, and 
proceed on their course to Haiti or Jamaica, or run for protection to 
the " Hawk's Nest," the name of the anchorage off the southern 
extremity of Grand Turk. Boats cannot ply between the islands, 
and communication is interrupted for days together when the weather 
is bad. Small craft accustomed to beat back from the islands to 



WEST INDIAN BEACH -DRIFT 9 



leeward now set their sails to the fair wind and accomplish in a few 
hours a passage that generally occupies days. At these times the 
stranding of drift on the eastern sides of the cays is suspended, and 
the drifting seed is beached on the western shores. This is an example 
of what must happen over much of the West Indian region when 
Nature for short periods breaks through her regime and quite different 
climatic conditions assert themselves. It will thus be understood 
how time would in the end prevent any marked differentiation in 
the distribution of littoral plants in the West Indian region. 

For a satisfactory study of the West Indian beach-drift it was neces- 
sary to find a place where the local flora could be largely excluded 
as a probable source of materials. In Jamaica, for instance, it was 
apparent that much of the beach-drift could have been furnished by 
the plants of the island ; and often the only indications of a foreign 
origin were the signs of long immersion in the sea afforded by in- 
crusting Serpulce, Balani, Polyzoa, etc., and by the borings of molluscs. 
But most of the stranded seeds did not display these evidences of 
a long ocean journey; and in such cases one could rarely be sure of 
one's ground. 

This was one of the reasons why I selected the Turks Islands at the 
south-eastern end of the Bahamas for a more thorough examination 
of West Indian seed-drift. Almost all of the larger fruits and seeds 
that are stranded on the eastern beaches of the various islands or 
cays, making up this little archipelago, belong to plants that are not 
only absent from this small group, but are not included in the 
Bahamian flora. The flora of the Turks Islands, which I have dealt 
with briefly in Chapter XII., is largely littoral in character, almost 
entirely Bahamian in composition, and as such displays a combined 
West Indian and Florida fades. 

Author's Indebtedness to Dr. Millspaugh. — Having the good 
fortune to meet Dr. Millspaugh on Grand Turk, I thus acquired more 
precise notions of the relation between the stranded drift and the 
plants of this archipelago. Dr. Millspaugh very kindly lent me the 
manuscript of the Flora of the Bahamas, by Dr. Britton and himself. 
From its pages I obtained a general idea of the Bahamian flora, to 
which the plants of the Turks Islands belong. This generous loan 
of a work before its publication, a work representing the results of 
years of exploration and research, was quite spontaneous, and I 
shall always take a keen pleasure in recalling the circumstance. Its 
perusal enabled me to approach the subject of the relation between 
the plants represented in the beach-drift and the plants of the flora 
of the Turks Islands with far greater confidence than I should have 
otherwise possessed. 

But in another way the author is deeply indebted to the labours 
of the American botanists. One of the most methodical examinations 
hitherto made of the vegetation of the sand-islets of a coral-reef region 
was carried out in 1904 by Mr. O. E. Lansing in the sand-keys lying 
to the westward of Key West, Florida. He was commissioned by 
the Field Columbian Museum of Chicago; and his collections, com- 
prehensive notes, and maps form the subject of a paper on the 
Flora of the Sand-Keys of Florida, by Dr. Millspaugh in the publica- 



10 PLANTS, SEEDS, AND CURRENTS 



tions of the same institution (Bot. Ser. 1907). A discussion of this 
paper is given in Note 7 of the Appendix. I may remark that the 
Florida " key " is the equivalent of the Bahamian " cay," and 
that both terms will be employed here in their respective associations. 

The beach plants of the Turks Islands, which in the smaller cays 
occupy much of their surface, are, as a rule, common West Indian 
species and are generally distributed through the Bahamas, occurring 
also in the Florida keys. 

The Stranded Drift of the Turks Islands. — The mangrove 
formation, which is still fairly extensive in area on Grand Turk in 
spite of the salt-making industry, is very limited in its composition, 
and lacks most of the accessory plants that give variety to the great 
mangrove formations of the large West Indian Islands. In its 
restricted composition and in its constituent trees (Rhizophora mangle, 
Laguncularia racemosa, Avicennia nitida, with Conocarpus erectus at 
the borders) the mangrove belt of the islands of the Turks Group 
approaches very closely that of the Florida Keys. So abundant is 
the foreign drift on the beaches of the cays of the Turks Group that 
the seeds and fruits of the local mangrove and beach plants scarcely 
figure in it. Here we shall be concerned only with the larger stranded 
seeds and fruits from other regions. The smaller and local drift is 
discussed in Note 2 of the Appendix. 

During my sojourn of three months in the Turks Group I visited 
all the islands or cays, and collected or recorded about 2000 foreign 
seeds or fruits, all of them doubtless derived from the islands to the 
southward and eastward, San Domingo, Porto Rico, and the Leeward 
Islands. In Note 13 of the Appendix it is shown from the indica- 
tions of bottle-drift stranded on the south-eastern Bahamas, and from 
the course taken by bottles dropped into the sea in this neighbour- 
hood, that the prevailing set of the surface currents in this region 
is in a W.N.W. direction, and that the Turks Group lies in the track 
of drift on its way in the Antillean Stream from the islands to the 
eastward and southward to the Florida Straits, where it gets within 
the influence of the Gulf Stream. 

The analysis given below illustrates the relative frequency of the 
several kinds of seeds and fruits that figure in the beach-drift. As 
above remarked the local seed-drift is derived from plants growing 
in the vicinity, whether in the mangrove swamps or on the sandy 
beaches, the present discussion being almost exclusively restricted 
to the seeds and fruits of plants not growing on the islands, the local 
materials being largely disguised by the mass of drift from a distance. 

There are, however, named in this list the seeds of Guilandina 
bonducella, which grows in the larger islands of the Turks Group away 
from the beach. But since these drift seeds were best represented 
on Greater Sand Cay at the southern end of the group, a cay which 
does not possess the parent plant but is the first to receive the foreign 
drift, it is apparent that they must be included in the list. 

Some of the drift is washed into the interior of the cays during 
hurricanes, and may be found between the sand-hills a hundred 
yards and more from the beach. It will be noticed in the following 
table that more than half of the foreign seeds and fruits stranded 



WEST INDIAN BEACH-DRIFT 



11 



on the beaches of the Turks Islands would be able to reproduce the 
plant. 

Table Showing the Constituents of the larger Drift Stranded on the 
Eastern Shores of the Turks Islands, all being of Foreign Origin. 

(The numbers illustrate their relative frequency. Leguminous plants are marked 
L, and palms P. Further details respecting distribution, station, and other matters 
will be found on the pages indicated.) 





Fruit (F) 


Number 




Pages for 




or 


per 


Condition of Seed 


further 




Seed (S) 


Thousand 




Details 


L. Ecastaphyllum (?) 


F 


200 


Decaying or decayed . 


111 


Spondias lutea 


F 


200 


Usually sound .... 


111 


Hippomane mancinella 


F 


110 


Sound 


113 


Terminalia katappa 


F 


108 


Sound 


116 


L. Entada scandens . 


s 


100 


Sound 


117 


L. Mucuna urens (and an 










allied species) . 


s 


60 


Sound 


120 


Fevillea cordifolia . 


s 


50 


5% apparently sound . 


124 


P. Manicaria saccifera 


F 


40 


2% sound 


127 


L. Dioclea refiexa . 


s 


14 




130 


Sacoglottis amazonica . 


F 


14 


A few fruits with sound 










seeds 


133 


L. Guilandina bonducella 


s 


10 


Sound 


138 


L. Hymen sea courbaril 


F 


10 


Some seeds sound . 


140 


Carapa guianensis . 


s 


10 


10% appear sound 


141 


Mammea americana . 


F 


6 


Germinative capacity 


144 


Crescentia cujete . 


F 


4 


Dead 


145 


Crescentia cucurbitina . 


F 


2 


Dead 


147 


L. Andira inermis 


F 


3 


Germinative capacity 


150 


L. Cassia grandis . . . 


F 


3 


A third of the seeds sound 


152 


L. Cassia fistula 


F 


2 


A sixth of the seeds sound 


152 


Calophyllum calaba 


F 


2 


Decaying or decayed . 


155 


Sapindus saponaria 


S 


2 


Not examined .... 


156 


L. Drepanocarpus lunatus 


F 


1 




159 


Omphalea diandra. 


s 


1 


Germinative capacity 


159 


P. Acrocomia .... 


F 


1 


Fruits empty .... 


160 


Ipomcea tuberosa . 


s 


1 




161 


Mangifera indica . 


s 


46 




164 






1000 







We find washed up on the weather beaches of the Turks Islands 
almost all the larger fruits and seeds that are characteristic of the 
beach-drift over the West Indian region ; and they are all the more 
interesting in these islands because, with few exceptions, they are 
foreign to the local flora. 

Jamaican Beach-drift. — Almost all of them came under my notice 
in the beach-drift of the coasts of Jamaica. Amongst the exceptions 
are the seeds of Carapa guianensis and the pods of Hymencea courbaril. 
The first named, however, were included in a collection of Jamaican 
beach-drift sent by Mr. Morris (afterwards Sir D. Morris) to Kew 
about thirty years ago, the contents of which are given in the list 



12 PLANTS, SEEDS, AND CURRENTS 



appended. But this list is only partly illustrative of Jamaican drift, 
and principally of the larger fruits and seeds. To supplement it we 
should have to add many of the names of the beach plants con- 
tributing regularly to West Indian stranded drift which are given 
in the list on page 5, such as Canavalia obtusifolia, Chrysobalanus 
icaco, Coccoloba uvifera, Conocarpus erectus, Hippomane mancinella, 
Sophora tomentosa, Thespesia populnea, etc. ; and besides there would 
be the mangroves (Rhizophora, Laguncularia, Avicennia) already 
discussed in this chapter, as well as Mammea americana, Grias 
cauliflora, etc. All the seeds and fruits most typical of West Indian 
beach-drift may be found on the coasts of Jamaica. But the point 
with which we are more immediately concerned here is that almost 
all the larger foreign drift stranded on the Turks Islands can be found 
on the Jamaican beaches. 

List of Seeds and Fruits washed Ashore at the Palisadoes 
Plantation on the South Coast of Jamaica, being a Collection 
sent to Kew by Mr. Morris about 1884, and described by 
Mr. Hemsley in Part IV. of his Work on the Botany of the 
"Challenger^' Expedition (1885). 

The localities in which the different seeds and fruits have been 
found by me in the West Indian beach-drift are indicated by abbre- 
viations explained below. The drift specimens not named by Mr. 
Hemsley but since identified are marked *. 

Calophyllum calaba. Tur., Jam. 
*Sacoglottis amazonica. Tur., Jam., Trin., Col. 

Carapa guianensis. Tur., Trin. 

Spondias lutea. Tur., Jam., Trin., Col. 
*Dioclea reflexa. Tur., Jam., Trin. 

Mucuna urens. Tur., Jam., Trin., Col. 

Mucuna sp. Tur., Jam., Trin. 

Ecastaphyllum brownei. Jam., Col. 

Guilandina bonduc. 

Guilandina bonducella. Tur., Jam., Trin. 
Cassia fistula. Tur., Trin. 
Dimorphandra mora. Trin. 
Entada scandens. Tur., Jam., Col. 
Fevillea cordifolia. Tur., Jam., Trin. 
Ipomcea pes-caprae. Tur., Jam., Trin., Col. 
*Ipomcea tuberosa. Tur., Jam. 
Omphalea diandra. Tur., Trin. 
Juglans sp. Trin. 

Manicaria saccifera. Tur., Jam., Trin. 
Astrocaryum sp. Trin., Col. 

Under their respective headings in a later part of this work will be 
found the accounts of the identification by Sir D. Morris and by 
Mr. Hemsley of the fruits or seeds of Sacoglottis and of Ipomoea 
tuberosa. The seeds of Dioclea reflexa are included in the Morris 
collection in the Kew Museum. 



WEST INDIAN BEACH-DRIFT 



13 



Explanation of the abbreviations. — Tur. = Turks Islands; Trin. = 
Trinidad and the adjacent islands of Tobago and Grenada; Jam. = 
Jamaica; Col. = Colon. 

Xote. — Further details concerning the condition in which the seed 
and fruits occurred in the drift and other particulars will be found 
on the pages shown in the index. 

Beach-drift of Trinidad and the Neighbouring Islands of 
Tobago and Grenada. — In the same way almost all the larger 
fruits and seeds most frequent in the beach-drift of the Turks Islands 
came under my notice on the beaches of Trinidad, Tobago, and 
Grenada. An important exception existed in the seeds of Entada 
seandens, a plant that is not a member of the floras of this part of the 
West Indian region, and is seemingly absent from those of the district 
of the Amazon and the Orinoco. Together with much strange drift 
on these beaches I found the fruits and seeds of Carapa, Cassia, 
Crescentia, Dioclea. Fevillea, Hippomane, Mammea, Manicaria, 
Omphalea, Mucuna, SacogJottis, and Spondias named in the Turks 
Islands list. Fruits of palms are also frequent, including those of 
Astrocaryum and Bactris, the last probably derived from the palms 
growing in the coastal swamps of the locality. 

But on the Trinidad and Tobago beaches occurs much drift that 
is strange to the West Indian region, and is evidently derived from the 
Orinoco district as well as from the rivers of the Guianas and from the 
valley of the Amazon. Amongst the leguminous seeds are those of 
a species of Mucuna, 1| inches across (its incrusting marine organisms 
often telling a story of a long sea-passage), and the seeds of a species 
of Guilandina unknown to me from elsewhere. References to the 
seeds of these plants will be found later. But there is much of the 
strange drift piled on the south coasts of Trinidad that would 
not withstand long immersion in the sea. This is certainly true of 
a remarkable fruit which, as Prof. Pax informs me, seems to be a 
species of Hippocratea ; but several of the other fruits and seeds 
have not been identified. 

Amongst the unusual objects thrown up on the coasts of Trinidad 
are the huge brown embryos, three to four inches long and bare of 
coverings, of Dimorphandra mora, a common leguminous forest tree 
of British Guiana and also a native of this island. I was not aware 
of their identity until I recognised them in the Kew Museum. Accord- 
ing to Hemsley the embryo of this tree is one of the largest in the 
vegetable kingdom (Chall. Bot., IV., 301). An empty pod was in- 
cluded in the Morris collection of Jamaican beach-drift. These 
naked seeds are of a very tough, durable nature ; but it seems scarcely 
likely that they would retain their vitality after prolonged notation 
in the sea. 

Another singular woody fruit, top-shaped, deeply grooved, and 2J 
inches in size, is identical with a fruit which is named Juglans jamai- 
censis in the drift collection of the Kew Museum, and is perhaps the 
one referred to by Hemsley under Juglans with a query in his account 
of the Morris collection (Ibid., IV., 303). 

Drift on the Colon Beaches. — Much of the larger drift that is 



14 PLANTS, SEEDS, AND CURRENTS 



common to Trinidad, Tobago, Grenada, the Turks Islands, and 
Jamaica was observed by me at Colon on the extreme western border 
of the Caribbean Sea. On these beaches occurred the fruits and 
seeds of Hippomane mancinella, Manicaria saccifera, Mucuna urens t 
Sacoglottis amazonica, Spondias lutea, etc. Reference has already 
been made to one or two of the peculiar features of the beach-drift 
on the Colon side of the Panama Isthmus. 

The Absentees from the Beach-drift of the Turks Islands. — 
It is thus evident that most of the larger foreign drift of the Turks 
Islands is to be found on the beaches throughout the West Indian 
region. But the beach-drift of this small group does not contain all 
the larger fruits and seeds that in one locality and another are charac- 
teristic of West Indian drift ; and we shall see that their absence is 
significant of the weeding-out or exclusion of the drift least fitted for 
the accomplishment of the transatlantic passage, of which the Turks 
Islands represent the end of an early stage. For instance, it lacks 
the fruits of Grias cauliflora which are so characteristic of Jamaican 
beach-drift and are probably confined to that part of the West Indies. 
It lacks also the pods of Ecastaphyllum brownei, which form a common 
feature in the stranded drift of Jamaica and doubtless also of Cuba, 
as well as of the Caribbean side of the Panama Isthmus, as at Colon. 
Neither of these drift fruits seem to have been recorded from the 
stranded drift on the western shores of Europe, nor are they likely 
to be found there ; and their absence from the beaches of the Turks 
Islands is an indication of their unfitness for the ocean traverse. Nor 
do we find thrown up on the beaches of this outlying West Indian 
group several of the strange fruits stranded with much other Orinoco 
drift on the south coast of Trinidad, and doubtless not possessing 
great floating powers. 

Generally speaking (it may be added) I found nearly all the drift 
seeds and fruits on the Turks Islands beaches that my previous 
experience in other parts of the West Indies led me to expect. An 
exception, however, which is concerned with the absence of the empty 
fruits of Astrocaryum, a genus of palms, is dealt with on page 181, 
but it is highly probable that I overlooked them, since their occur- 
rence on the beaches of the Azores implies great capacity for transport 
by currents, though in an ineffective state. 

Oceanic Drift in Transit represented on the Beaches of 
the Turks Islands. — Since in this small group the local flora can 
be readily excluded, we are here presented with oceanic drift in 
transit. The drift here stranded is something more than a sample 
of the material that is for ever being drifted in the Antillean Stream 
westward and northward past and through the Bahamas towards 
the Florida Straits, where the Gulf Stream concentrates its energy 
before proceeding to traverse the North Atlantic. It represents the 
residue of all the vegetable debris (fruits, seeds, bark, leaves, branches, 
tree-trunks, etc.) brought down to the sea by the rivers, or carried off 
by the currents from the shores, of the large islands lying to the 
southward and eastward. Since much of this material possesses 
limited floating powers, it would go to the bottom in a short time. 
After drifting about for weeks or months the mass of vegetable debri,s 



WEST INDIAN BEACH-DRIFT 



15 



once very large, now very small, reaches the Turks Islands at the 
south-eastern extremity of the Bahamas. Depositing on those small 
islands a sample of its contents, it continues its drift westward and 
northward towards the last starting-point of the swift current of 
the Gulf Stream in the Straits of Florida before it begins the Atlantic 
traverse. 

How truly the sample represents the seeds likely to be drifted 
across the Atlantic is shown in the fact that practically all the seeds 
and fruits known to me as having been stranded on the coasts of 
Europe occur in the drift of the Turks Islands, making up as much as 
a third of the total. A list of them is given in the following chapter. 
We are thus able to detect at a glance the larger seeds and fruits 
of the drift which are most likely to accomplish the traverse of the 
North Atlantic without loss of the germinative capacity. The results 
obtained in the Turks Islands therefore fully justified my selection 
of this locality for the observation of Nature's method of sifting the 
drift of the West Indian region before it gets within the influence 
of the Gulf Stream in the Florida Sea. 

The Black River of Jamaica as a Source of a Drift. — As an 
example of the manner in which rivers convey seeds and fruits to 
the sea in the West Indian region, I will take the case of the Black 
River, the largest river in Jamaica. Above the mangrove belt of 
Rhizophora mangle, Laguncularia racemosa, and Avicennia nitida, 
all of them trees that contribute to the floating drift, one passes into 
a region where the Anchovy Pear (Grias caulifiora) is the most con- 
spicuous tree on the riverside, its large germinating fruits frequently 
floating past in the stream. Although in places taller trees closely 
line the river, it is the Anchovy Pear with its terminal head of large 
leaves, four or five feet long, and its flowers and fruits growing from 
the simple straight trunk, that first catches the eye. One of the 
loftier trees is the Paki tree (Crescentia cucurbitina), with its gourds 
hanging suspended over the water and often to be noticed floating 
down the river. A Crinum flourishes at the water's edge, its large 
fleshy seeds frequently occurring in the germinating condition in the 
floating drift. Here and there, hanging in leafy festoons from the 
tree branches as they spread over the water, is the Antidote Vine 
(Fevillea cordifolia), which with Grias caulifiora may be regarded as 
amongst the most interesting plants at the riverside. Its large fruits, 
like cannon-balls, were occasionally to be seen afloat. The Hog 
Gum tree (Symphonia globulifera), one of the Guttiferae, grows also 
on the banks, its large germinating seeds floating in numbers in the 
stream. 

Beyond the lower wooded district at the riverside, one passes into 
an open savannah-like region, much of which is swamp. It is known 
as the Great Morass, and is the home of the alligator. A reed-like 
growth of Typha, Papyrus-like Cyperi } and other tall sedges, which 
add little or nothing to the floating seed-drift, lines the banks; 
whilst clumps of Grias trees decked with Ipomceas occur at intervals 
by the water-side. In this open country, in places where the ground 
is rather drier, one notices on or near the banks various trees that are 
represented by their fruits or their seeds in the floating drift, such as 



16 PLANTS, SEEDS, AND CURRENTS 



Paritium (Hibiscus) elatum, Crescentia cujete (Calabash tree), and the 
Angeleen tree (Andira inermis). For miles inland this swampy plain 
extends. Above Lacovia the hilly country is entered, the banks 
steep and the slopes well wooded. Here reappear the Anchovy 
Pear tree, the Antidote Vine, the Angeleen tree, and Paritium 
elatum ; and amongst other trees occurs Crudya spicata, the large 
seeds of which, often as large as those of Entada scandens and possess- 
ing the same name of " Cocoon," may be observed floating in numbers 
in the germinating condition in the stream. Amongst the tall trees 
on the steep slopes grow Cassia grandis, the long pods of which occur 
in the floating drift, and a species of Ficus, the fruits of which could 
only float for a short time ; whilst Mucuna urens, a climber on the 
trees, adds its seeds to the floating drift. 

I have mainly referred to the vegetation that contributes to the 
floating drift of fruits and seeds carried by the stream. The clumps 
of tall Sabal palms (S. umbraculifera), that dot the surface of the 
Great Morass, make little or no addition to the drift, as the fruits 
possess but slight buoyancy, and the same may be said of other palms 
(Euterpe, etc.). The same remark applies to the climbing aroids 
(Syngonium and Philodendron) that often conceal the tree-trunks. 

But brief reference need here be made to a multitude of aquatic 
and subaquatic plants, Ceratophyllum, Nymphcea, Pontederia, Pota- 
mogeton, Sagittaria, Utricularia, etc., that, except in the fourth and 
fifth cases, were not represented by their seeds or their fruits in the 
floating drift. In the lower part of the river the floating seed-drift 
often accumulates amongst the patches of Water Hyacinth (Ponte- 
deria), and here may be found the Water Lettuce (Pistia) and 
portions of Azolla. In concluding these remarks on the Black River, 
I may call attention to the frequency of germinating fruits and seeds 
in the floating drift, as already noticed in the cases of Crinum, Crudya, 
Grias, and Symphonia. 

In the foregoing remarks the Great Morass of the Black River 
district is dealt with as a source of river-drift. A detailed description 
of it will be found in Chapter V. ; and there also will be found an 
account of the Great Morass of Westmoreland in the south-west part 
of the island. The Cabarita, one of the larger rivers that drain it, 
presents most of the characters of the Black River as regards vegeta- 
tion, though on a smaller scale. As will subsequently be shown, 
many of the conspicuous features of the Black River Morass are 
represented in the portion of the Great Morass of Westmoreland 
that extends westward from Savanna-la-mar to Negril, Grias cauli- 
flora being especially prominent on the banks of streams in this 
part of the island. 

The Roaring River Falls, Jamaica. — At these falls on the north 
coast of Jamaica there are some fine specimens of the Grias tree, 
which grows not only near the brink of the falls, but half-way down 
the precipitous slopes of calcareous tufa that form their face. At 
the cost of a wetting I clambered down the steep slopes to their base. 
Fruits carried over the falls have caught in crevices in their descent, 
and there germinating have developed into trees. Below the falls 
the Grias trees are associated with tall trees of Bucida buceras and 



WEST INDIAN BEACH-DRIFT 



17 



Crescentia cucurbitina. Prof. Harshberger, who visited this, locality, 
refers to the Bucida and Grias trees (Phyt. Surv. N. A?ner>, p. 678). 
The " olive tree," as the Jamaicans name Bucida buceras, iia charac- 
teristic swamp tree of the estuaries on the north side of the island. 
Owing to the lack of mature fruits the opportunity of studying this 
interesting tree from the standpoint of dispersal was not presented 
to me. 

Comparison of the Beach-drift on the Pacific and West 
Indian Coasts of Tropical America. — A few remarks may here 
be made on the small contrast that exists between the beach-drift 
on the Pacific coasts of tropical America and on the West Indian 
or Caribbean side. As discussed in the case of the Ecuadorian and 
Panama beach-drift in my book on Plant Dispersal (p. 498), many of 
the familiar mangrove and beach plants occur on both sides of the 
continent and add their fruits and seeds to the drift, such as Rhizo- 
phora mangle, Laguncularia racemosa, Avicennia nitida, Canavalia 
obtusifolia, Conocarpus erectus, Ecastaphyllum brownei, Hibiscus 
tiliaceus, Hippomane mancinella, Ipomcea pes-caprae, etc. To these 
may now be added Sccevola plumieri, a characteristic West Indian 
strand shrub that occurs also on the Pacific coasts. 

Equally common on the beaches of the West Indies and Colon on 
the Atlantic side and of Ecuador and Panama on the Pacific side 
are the seeds of Entada scandens and Mucuna urens and the fibrous 
" stones " of Spondias lutea. Much of the drift found afloat in the 
estuaries on the Pacific coast could be matched in those of the West 
Indian region, since many of the estuarine and swamp plants are the 
same. If we supplement the account given in my previous work of 
the drift carried down to the sea by the Guayaquil River in Ecuador 
with the names of two floating fruits not there identified, namely, 
the gourds of Crescentia cujete and the fruits of Grias cauliflora, we 
emphasise the resemblance between the character of the drift carried 
into the Pacific Ocean by the Ecuadorian rivers and of that dis- 
charged into the Caribbean Sea by the Black River in Jamaica. 
Amongst the beach-drift gathered by me on both sides of the Panama 
Isthmus were the large pods of Prioria copaifera, as identified at 
Kew. They seem to be quite useless for dispersal by currents, 
since the seeds of the fruits examined were always decayed. This is 
the type species of a genus which was first described by Grisebach 
(p. 215) from a rare Jamaican tree. 

There are, however, differences between the drift found on the 
Pacific and Atlantic sides. Thus since neither Manicaria saccifera 
nor Sacoglottis amazonica occur on the Pacific border of the conti- 
nent, their fruits have not been found in the drift. Here the empty 
seeds of the Vegetable Ivory palm, Phytelephas macrocarpa, con- 
stitute one of the principal features of the floating and stranded drift 
of coasts and estuaries in Ecuador, the sound seeds possessing no 
floating power. It is remarkable that this palm which abounds on 
the banks of the Magdalena River does not contribute to West Indian 
drift. We learn from Spruce's Notes of a Botanist on the Amazon 
and in the Andes that the Eastern and Western Andes possess in each 
case a separate species of the genus, 
c 



18 PLANTS, SEEDS, AND CURRENTS 



Summary 

1. After remarking that beach-drift has much the same general 
characters over the West Indian region, it is pointed out that its 
principal sources are the plants of the beach, of the coastal and 
estuarine mangrove swamps, and of the riverside in inland districts 

( P . i). 

2. Whilst the beaches near an estuary in a large island are the most 
suitable localities for the drift in the mass, it is in the low islet lying 
far out to sea that we find the best opportunity of investigating the 
portion of it that is most fitted for oceanic transport. Such an islet 
receives only the residue of a vast amount of vegetable debris which 
for the most part soon goes to the bottom (p. 2). 

3. The distinction is drawn between local and foreign beach-drift, 
the latter which is derived across the sea from other islands being 
likely to be masked by the local materials (pp. 2, 3). 

4. As illustrating the part taken by rivers above the mangrove- 
lined estuary in supplying drift to the beaches, the Black River of 
Jamaica is taken as an example; and it is shown that on account 
of the tendency to germinate when afloat many of the seeds and fruits 
of riverside plants have little or no effective value for over-sea dis- 
tribution (p. 3). In others again the floating power is either absent 
or slight; whilst there may be cases where the buoyancy is great, 
but the seeds have a fleeting vitality and soon decay. The con- 
clusion is formed that not one-fifth of the seeds and fruits brought 
down by a West Indian river from inland districts to the sea would 
be capable of reproducing the plant after a traverse of a hundred 
miles of ocean (pp. 4, 5). 

5. The mangrove formation as a source of drift is next discussed. 
It is shown that whilst the true mangroves (Rhizophora, Laguncu- 
laria, Avicennia) are in one form or another well adapted for over- 
sea transport, in the case of their associates (Anona, Carapa, Manx- 
caria, Sacoglottis, etc.) the floating seed or fruit has many difficulties 
to contend with, which considerably restrict their capacities for 
effective distribution by currents (pp. 4, 5). 

6. Then the plants of the beach-borders are dealt with from the 
same standpoint, and a list is given of West Indian beach plants 
commonly represented in the drift. It is remarked in passing that 
in their much smaller size the fruits of West Indian beach trees offer 
a great contrast to those of the trees of the far more luxuriant beach 
vegetation of the tropical islands of the Indian and Pacific Oceans 
(pp. 5, 6). 

7. The difficulty in discriminating between local and foreign drift 
is again alluded to, and reference is made to the sorting out by the 
waves of the finer and larger components of the beach-drift (p. 6). 

8. Whilst fresh emphasis is laid on the uniformity in general 
characters of the beach-drift of the West Indian region, it is shown 
that each locality may present some peculiar feature (p. 6). 

9. The author then refers to his method of identifying the con- 
stituents of the drift (pp. 7, 8). 

10. The distribution over the West Indian region of the seeds and 



WEST INDIAN BEACH-DRIFT 



19 



fruits brought north from the estuaries of the Orinoco, the Guiana 
rivers, and the Amazon is discussed (p. 7). 

11. Reasons are given for the belief that however uniformly 
surface currents seem to act in distributing the seeds and fruits of 
littoral plants in this region, Nature in the course of ages breaks 
through her regime frequently enough to prevent any marked differ- 
entiation in the distribution of littoral plants (p. 8). 

12. The author then deals with his selection of the Turks Islands 
at the south-eastern extremity of the Bahamas for the methodical 
investigation of the drift fruits and seeds best adapted for oceanic 
transport, one of the principal reasons being that here it would be 
easy to exclude the drift of local origin. The results proved the 
correctness of this surmise, since almost all the larger fruits and seeds 
in the beach-drift of these islands belong to plants that are strangers 
to the Bahamas (p. 8). 

13. A detailed account of the drift stranded on the Turks Islands 
is given, with a tabulated analysis showing the relative frequency of 
the constituents of the foreign fruits and seeds, and the conclusion 
is formed that almost all that are characteristic of West Indian drift 
have been carried there by the currents (p. 10). In confirmation 
of this conclusion a comparison is made with the beach-drift of 
other West Indian localities, such as Jamaica (p. 11), Trinidad (p. 13), 
etc. 

14. The beach-drift of the Turks Islands is thus considered as 
representing oceanic drift in transit. After drifting about for weeks 
or months the mass of vegetable debris, once very large, now very 
small, reaches this group. Depositing on these small islands a 
sample of its contents, it continues its passage in the Antillean 
Stream towards the Florida Straits, where the Gulf Stream gathers 
its energy before commencing its Atlantic traverse. How truly the 
sample represents the materials likely to be drifted across the Atlantic 
is shown in the fact that one-third of the fruits and seeds that figure 
in the foreign drift of the beaches of the Turks Islands have been found 
stranded on the coasts of Europe (p. 14). 

15. A more detailed description is given of the vegetation of the 
Black River as a source of drift (pp. 15, 16); and the chapter is con- 
cluded with a comparison of the beach-drift on the Pacific and Carib- 
bean sides of tropical America, in which it is shown that although 
there is a close resemblance in general composition there are important 
differences in details (p. 17). 



CHAPTER II 



WEST INDIAN DRIFT ON EUROPEAN SHORES 

In order to give point and method to my numerous observations 
on the dispersal of plants by currents in the West Indian region, 
as illustrated by the examination of the beach-drift and by various 
buoyancy experiments, I will at first let the discussion centre around 
the fact that some of the materials reach the shores of Europe. 

The Literature of the Subject. — Although it is not possible 
for me to deal exhaustively with the numerous references to the 
occurrence of West Indian seeds and fruits on the coasts of Europe 
which have been made since De FEscluse, " better known under the 
Latinised appellation of Clusius," first figured some of them, in ignor- 
ance of their origin, in his Exoticorum Libri in 1605, the history of the 
subject will be found treated with some detail in this chapter. Those 
curious in the matter will find an excellent general account of our 
knowledge up to the middle of last century in Dr. Gumprecht's 
Die Treibproducte der Stromungen in Nordatlantischen Ocean (1854). 
His object was to sum up the evidence supplied by the variety of 
natural products from tropical regions thrown up on the north-west 
coasts of Europe in favour of the extension of the Gulf Stream into 
high northern latitudes, a theory that had been vigorously opposed 
by Rennell and others. It is difficult for us to realise that such a 
necessity ever existed. Yet it did ; and one result was the publica- 
tion of this paper in the Zeitschrift fur Allgemeine Erdkunde on the 
drift-materials transported by the North Atlantic currents, in which 
almost all the facts then known were gathered together and discussed 
with the usual German acumen and thoroughness. 

The subject of the West Indian drift on European beaches was 
dealt with by numerous writers during the last century in their 
treatment of the currents of the North Atlantic. Amongst them may 
be mentioned Humboldt in his Voyage aux regions equinoxiales, 
Paris, 1807, etc. ; Sartorius von Waltershausen in his Physisch- 
geographische Skizze von Island, 1847 ; Schjoth in his work on different 
marine phenomena (Om enkelte af Havets Phdnomene, Christiania, 
1848) ; Irminger in his paper on the ocean currents (Zeitsch. fur 
Allgem. Erdk. 1854) ; Fogh in a paper on the Gulf Stream in Tidds- 
skrift for populcere Fremstillinger af Naturvidenskaben, Copenhagen, 
1857, where he gives a sketch of the history of our acquaintance 
with the subject ; Vibe, chief of the Norwegian General Staff Survey, 
in his Kusten und Meer Norwegens, published in a supplementary 
volume of Petermann's Mittheilungen (1859-61); and Kohl, who in 

20 



WEST INDIAN DRIFT ON EUROPEAN SHORES 21 



his Geschichte des Golfstroms, Bremen, 1868, also deals with some 
of the earlier references. 

Amongst those who have specially dealt with the botanical side 
of the subject in recent years are Hemsley, Lindman, and Sernander. 
The two last named were exclusively concerned with the drift of 
the Scandinavian beaches, and their results are given by Sernander 
in his work on the " distribution-biology " of the Scandinavian 
plant- world (Upsala, 1901). The first named reopened the whole 
inquiry in his botanical contribution to the reports of the Challenger 
Expedition, and in its pages largely guided the investigations of 
later students like myself. But it would be unjust if one did not 
refer to one of the old veterans who did so much to establish clear 
conceptions concerning the nature and source of the foreign seed- 
drift on our European coasts. In the foremost place comes Sir 
Hans Sloane, who from experience derived from a sojourn of fifteen 
months in Jamaica, 1688-9, was enabled to identify the names and 
determine the origin of several of the strange seeds and fruits stranded 
on the Irish and Scottish coasts and on the islands to the north, 
his results being given in the Philosophical Transactions for 1695-7, 
and in the account of the natural history of Jamaica, which occupies 
most of his work on the West Indies. He naturally came to the 
conclusion that these West Indian seeds had been brought by the 
" Currents and Seas." 

The early Scandinavian References.- — It is interesting to 
notice how in Scandinavia the crude surmises of the early writers 
on the natural history of these regions gave place to the more accurate 
determinations of the Linnean school of botanists. In the first 
place stands Peter Claussen (Peder Clausson), the Norse writer, who 
in his Description of Norway published in 1632, nine years after his 
death, refers to the seeds of Entada scandens as " stones floated 
on to the coast," both in Scandinavia and the Faroe Islands. 
Claussen was merely reiterating the old Norse belief, which found 
expression in such names as " adder-stones," " eagle-stones," etc., 
that were applied to these drift seeds, a matter mentioned again in 
a later page of this chapter. One of the earliest to perceive their 
real nature was Olaus Worm, a Danish naturalist of the seventeenth 
century, whose Epistolce are quoted by Gumprecht (p. 420). He 
determined them to be leguminous, and referred them to two genera 
of Indian beans. Amongst the first to recognise their place of origin 
was Provost Lucas Jacobsen Debes, who in his Faeroa Reserata or 
Faeroe Revealed, published at Copenhagen in 1673, stated his opinion 
that the seeds came from the West Indies and were " brought hither 
by the Stream." This early reference to the Gulf Stream striking 
the north-west shores of Europe may merit the attention of the 
geographical student. 

But the popular notion as to their inorganic origin long survived, 
and it succumbed only to give place to another erroneous idea that 
they were the product of marine plant-like organisms, such as the 
" alcyonarian sea-shrubs." Thus Pontoppidan, the famous Bishop 
of Bergen, in his book on the Natural History of Norway, which was 
issued at Copenhagen in 1751, gave the name of Faha marina, or Sea 



22 



PLANTS, SEEDS, AND CURRENTS 



Bean to the stranded seeds of Entada scandens, regarding them as the 
products of the " sea-trees " (sea-fans, etc.). These " sea-shrubs " 
may attain a considerable size on our coasts. Sloane, who in his return 
voyage from the West Indies touched at the Scilly Islands, writes (II., 
347) that " on these rocks grows the Frutex marinus, flahelliformis" 
a specimen seen by him having " such dimensions and beauty that 
King Charles II. kept it many years, even to his death, for the orna- 
ment of his closet." 

Sea Bean and Sea Nut are names still applied, as I found, in various 
parts of the world to the seeds of Mucuna and Entada when picked 
up either afloat in the sea or stranded on the beach ; and one hears 
at times some singular opinions as to their origin. On one occasion 
I had a difficulty in persuading a gentleman, who wore a seed of 
Mucuna urens as a charm on his gold chain, that it was not some 
spontaneous production of the waves. The appellation of Gulf 
Nut, used at times by those who gather these seeds on European 
beaches, would be more appropriate. 

Gunnerus, Bishop of Drontheim, and Strom, the Norwegian 
naturalist, first supplied the materials for the identification of the 
tropical elements of Scandinavian beach-drift to the Linnean botan- 
ists; and, as Sernander points out (p. 116), it is through the work 
of Tonning, a pupil of Linnaeus, that their observations are usually 
known to the world (Amcen. Acad., VII). Although seemingly 
not acquainted with Sloane's writings, Gunnerus formed independ- 
ently the same conclusions respecting the origin of the foreign seeds 
and fruits in the drift. His observations were published in the 
memoirs of the Drontheim Society (Copenhagen, 1765); and the 
results together with the botanical identifications of the plants were 
incorporated by Tonning in his paper. Strom refers to the foreign 
drift in his description of the bailiwick of Sondmore, published in 
1766, a work quoted by Gumprecht (p. 420). I do not gather that 
the matter attracted the special attention of Linnaeus beyond the 
fact that in the following volume of the Amcenitates he cites, in 
illustration of the ocean's part in seed-distribution, the seeds and 
fruits washed up on the coasts of Norway, as specified by Tonning. 

The Early Scottish References. — In their quaint descriptions 
of the Hebrides, the Orkneys, and the Shetland Islands, the old 
authors often give prominence to the foreign drift seeds stranded on 
their shores. Under the curious name of " Molucca Beans " we find 
their virtues described, both real and imaginary. Master James 
Wallace, minister of Kirkwall, in A Description of the Isles of Orkney 
published in 1693, and his son, Dr. James Wallace, F.R.S., in the 
edition of his father's book, which was issued with additions in 1700, 
were among the first to direct the attention of British naturalists 
to this matter. In 1703 Mr. Martin Martin, a native of the Hebrides, 
gave to the world an account of these islands in A Description of 
the Western Islands of Scotland, where he dwells especially on the 
medicinal virtues of the " Molocca Beans " and on their efficacy 
as charms against the " evil eye." Mr. Thomas Pennant in A 
Voyage to the Hebrides in 1772 places these " nuts commonly called 
Molucca Beans " amongst the amulets employed by the islanders. 



WEST INDIAN DRIFT ON EUROPEAN SHORES 23 



In the foregoing pages I have paid the debt due to many of my 
earlier predecessors in this line of research, and must refer the reader 
for a fuller description of many of the works named to the biblio- 
graphy at the close of this chapter. 

The Original Popular Names in Europe of the West Indian 
Drift Seeds and the Superstitions connected with them. — 
Reference has already been made to " Molucca Beans " as the name 
of these seeds in the Hebrides and Orkney groups in the latter part 
of the seventeenth century. Its origin is obscure. The younger 
Wallace (1700) particularly observes that he did not know the reason 
of this name as used by the Orkney islanders; but Sloane in his 
Natural History of Jamaica (II., 41), published a few years after, 
states that the seeds 44 are called Molucca Beans by the Inhabitants 
of Scotland, they supposing them to have come from those islands 
by an imaginary North East Passage." Several writers quote in 
this connection the Scotia Illustrata of Sir Robert Sibbald, Geographer 
Royal to Charles II., a work issued in 1694 ; but he merely includes 
Phaseoli Molucani in a catalogue of marine plants and other things 
M quae in Mari proveniunt " (II., lib. 4, p. 55). The appellation is em- 
ployed in dictionaries of the Scottish language in the interpretation of 
the vernacular names applied to the foreign seeds of the beach-drift, 
a matter alluded to later in this chapter ; but no endeavour to throw 
light on the origin of the epithet " Molucca " came under my notice. 
It is, however, noteworthy that both Martin and Sibbald in the 
works above quoted use the expression 44 Indian Nuts " or Nux 
Indica to distinguish one or more of the Molucca Beans. 

Gumprecht (p. 420) gives a number of Scandinavian vulgar names 
of these drift seeds, as obtained from the older Norwegian writers, 
names which indicate the prevalent superstitious beliefs connected 
with their origin 44 Ormesteen " or Adder- stone, 44 Losningsteen " or 
Solvent-stone, 44 Buesteen " or Bent-stone, are some of the old Norse 
names cited. The first was probably applied to the pale-coloured 
marble-like seeds of Guilandina bonducella, and the third to the seeds 
of Erythrina on account of their form. The Solvent-stone, according 
to Tonning, was the name of the large seed of Entada scandens, 
doubtless in indication of some special virtue attributed to it by the 
people. 

It was around the Entada seeds that superstition often centred. 
Debes, the historian of the Faroe Islands, displays some irritation 
against Claussen who credited the Faroe islanders with the Norwegian 
belief that one of these seeds 44 doth bring forth another stone when 
it is kept long." 44 It is very certain " (Debes goes on to explain) 
" that these seeds are found here ; but the inhabitants have not that 
superstitious opinion of them. Neither is it any stone, but a West 
Indian bean, as hath been told me by a very knowing man." Debes 
wrote his book about 1670. It was published in Copenhagen in 
1673, and the English translation by J.S. (identified in the British 
Museum catalogue as John Sterpin) was issued in London in 1676. 
We learn from Debes and Claussen that both in the Faroe Islands 
and in Norway the seeds of Entada scandens were named 44 Vette 
Nyre." This is translated by Sterpin as 44 Fairies' Kidneys " ; but 



24 PLANTS, SEEDS, AND CURRENTS 



Gumprecht (p. 417) turns it into German in the shape of " Fette 
Niere," of which " Fat Kidney " would be the English equivalent. 
Both in colour and form these seeds might be compared with kidneys, 
and Sterpin's rendering is the one adopted in the pages of Fogh, Vibe, 
and Kohl, the name being regarded as the equivalent of the German 
" Zauber-Nieren " (magic or fairy kidneys), which becomes intelligible 
in the light of the employment of these drift seeds as charms. 

It is, therefore, not a matter for surprise that these strange seeds 
when picked up on the beaches of north-western Europe have been 
used as charms. We have already remarked on their employment 
for this purpose. Pennant, as we have seen, in his book on the 
Hebrides classifies them among the amulets. But it is to the earlier 
work of Martin on the same islands that we are indebted for particu- 
lars in this respect. Of the seeds stranded on the island of Harris 
he writes : " There is a variety of nuts, called Molluka Beans, some 
of which are used as Amulets against Witchcraft or an Evil Eye, 
particularly the White one, and upon this account they are Wore 
about Childrens Necks, and if any Evil is intended to them, they say 
the Nut changes into a black colour. That they did change colour 
I found true by my own observation, but cannot be positive as to 
the Cause of it." (This white nut is evidently the seed of Guilandina 
bonducella.) Martin goes on to say that it is called " Virgin Marie's 
Nut," and he gives an instance of its effect in removing the spell of 
witchcraft from cows which gave blood instead of milk. 

Whilst noticing the employment of these drift seeds as charms one 
may direct attention to an interesting observation made by Hemsley 
in the Annals of Botany for 1892. He refers to a peculiar virtue 
which not so long ago the people of the Hebrides ascribed to the 
black seeds of Ipomcea tuberosa, one of the most remarkable of the 
West Indian seeds thrown up on those islands. He is quoting from 
an extract of the journal of Colonel H. W. Fielden, which was sent 
with one of these seeds to Kew about 1891. The specimen was 
given to this officer by a woman of North Uist, in whose family it 
had been kept for a couple of generations. Known amongst the 
Roman Catholic inhabitants of Long Island under a Gaelic name 
signifying " Mary's Bean," it was believed to ensure easy delivery 
when clenched in the hand of a woman in childbirth. 

Doubtless the belief in the protective powers of the West Indian 
seeds thrown up on their coasts yet lingers with the fisherfolk of 
the Scottish islands ; and in the Shetlands, as I have been told, the 
wives of the fishermen still make ornaments of them. But these 
islanders appreciate these gifts from the waves in another way. 
Martin tells us of the medicinal uses to which the Hebrideans and 
the people of Mull put the Molucca Beans or Indian Nuts. We are 
informed that for the cure of dysentery and similar complaints the 
powdered kernels of the black " Molocca " Bean (Entada scandens) 
and of the " white Indian Nut " (Guilandina bonducella) when drunk 
in boiled milk are " by daily experience found to be very effectual." 
One would have scarcely expected the seeds of the last named to 
be very efficacious ; but Sloane states (II., 41) that numerous virtues 
were ascribed to the seeds of Guilandina bonducella in the West 



WEST INDIAN DRIFT ON EUROPEAN SHORES 25 



Indies, and that their medicinal value was greatly esteemed by 
the Turks. 

Almost everywhere on the European shores of the Atlantic the 
stranded seeds of Entada scandens seem to have been used as snuff- 
boxes; and in some places they served as tinder-boxes or match- 
boxes. Many of the old authors (Sibbald, Debes, the two Wallaces, 
Sloane, etc.) allude to the snuff-boxes improvised from these seeds 
on the north-west coasts of Scotland, the Orkney Islands, and the 
Faroe Islands ; and it is evident from the condition of seeds sent to 
me from the Shetland Islands that the islanders utilised them for 
one or other of these purposes. In Scandinavia they were also thus 
employed. Thus De Capell Brooke, in his account of his travels 
in these regions in 1820, refers to the conversion by the Sea Finns of 
the seeds of Entada scandens into snuff-boxes. 

According to Martin the " black " Molucca Bean was specially 
named " Crospunk " in the Hebrides. In Warrack's A Scots Dialect 
Dictionary (1911) this name is applied to " the Molucca beans drifted 
to the shores of some of the western islands " ; but no etymology 
is given. This information was apparently derived from Jamieson's 
Etymological Dictionary of the Scottish Language, in which Martin 
is quoted as the authority. The suggestion in Jamieson's work 
(edit. 1879) that the word " would seem literally to mean in Gaelic 
the point of the cross " can scarcely be sustained, since a more probable 
origin presents itself in the old Scottish term spunk-box for match- 
box or tinder-box. Evidently the large seeds of Entada scandens 
are here implied. We have already noted their use as snuff-boxes, 
match-boxes, etc., and the writer has himself found them in use as 
match-boxes at the present day in several of the tropical homes of 
the plant. Originally the spunk-box was the Hebridean's tinder-box 
and afterwards his match-box; and when the West Indian drift 
seed served the same purpose he gave it the same name. The prefix 
need present no difficulty, since in Gaelic cro is a prefix possessing 
among other meanings those of witchcraft and sorcery. (See 
Dictionarium Scoto-Celticum, a Dictionary of the Gaelic Language : 
Edinburgh, 1828.) On this view crospunk might signify " the 
magician's tinder-box." We have already seen that in the Faroe 
Islands nearly two and a half centuries ago the same West Indian 
drift seed was known as Fairy's Kidney. 

Before discussing the West Indian seed-drift of European beaches 
according to the localities in which it has been found, I will give the 
list of the seeds and fruits that are most characteristic of it(pp. 26, 27). 

It is doubtful whether the seeds of any but the leguminous 
plants in the following list would retain their germinative capacity, 
which, it may be observed, has been established in the cases of the 
Entada, Guilandina, and Mucuna seeds. It would be hopeless to 
attempt to raise plants from the Manicaria specimens, and the 
result would be uncertain in the case of Sacoglottis and Sapindus. 
The prospects of success would be greater with Ipomcea tuberosa. 
The seeds of Crescentia gourds would be lifeless, and the fruits of 
Astrocaryum would be empty. Dioclea seeds would be sound, and 
Erythrina seeds might preserve their vitality. 



26 PLANTS, SEEDS, AND CURRENTS 



List of the Characteristic West Indian Drift Seeds and Fruits 





France 
(north 
coast) 


England 
(southern 
and south- 
western 
coast) 


Wales 
(south 
coast) 


Ireland 
(west 
coast) 


SCOTLAND 

(west 
coast) and 
Hebrides 


Orkneys 


I. 


Sacoglottis 
amazonica 
(Humiriacese) 




+ 






+ 




II. 


Sapindus 
safonaria 
(Sapindaceae) 














III. 


Gtjilandina 
bondtjcella 
(Leguminosae) 




+ 




+ 


+ 


+ 


IV. 


Entada 
scandens 
(Leguminosae) 


+ 


+ 


+ 


+ 


+ 


+ 


V. 


Mucuna tjrens 
(Leguminosae) 




+ 




+ 


+ 


+ 


VI. 


Mucuna near 

TJRENS 

(Leguminosae) 








-f 


+ 


+ 


VII. 


DlOCLEA 
REFLEXA 

(Leguminosae) 












+ 


VIII. 


Erythrina 
(Leguminosae) 












+ 


IX. 


Ipomcba 
tuberosa 
(Convolvulaceae) 










+ 


+ 


X. 


Gourds 

(Crescentia ? 
Bignoniaceae) 














XI. 


Manicaria 
saccifera 
(Palmaceae) 














XII. 


ASTROCARYUM 

(Palmaceae) 















1 The details for all the plants in this list 



WEST INDIAN DRIFT ON EUROPEAN SHORES 27 



FOUND ON THE BEACHES OP WESTERN EUROPE AND OF THE AZORES. 1 





Shbt- 

LANDS 


Faroes 


Uxw WAX, 

Sweden, 
Denmark, 
and 
Baltic 
Coasts 


Azores 


Remarks 


; 




















+ 




1 




+ 


+ 


+ 






+ 


+ 


+ 


+ 








+ 


+ 




For reasons given in the separate 
treatment of the genus it is probable 
that some of these records should be 
referred to the species below. 




+ 




+ 


+ 


Evidently the type of Mucuna seed 
most frequently gathered on the 
beaches of Europe. (See above re- 
mark. ) 




+ 








Probably a few of the Mucuna 
records were referred to this species. 








+ ? 




Ti • • 1 j V ill "XT _ 

It is surmised that the JN orse name 
of Buesteen (G. Bogensteine; E. 
Bentstone) was applied to a species 
of Erythrina. 




+ 




+ ? 




It may be that the large Convol- 
vulaceous seed found by Lindman on 
the coast of Norway in 1880 belongs 
to this species. 








+ ? 




In the special treatment of Gourds 
found on European beaches it is 
shown that they are more likely to 
belong to the genus Crescentia than 
to that of Lagenaria. 



























will be found by consulting the Index. 



28 



PLANTS, SEEDS, AND CURRENTS 



There have also been recorded from European beaches such 
tropical fruits as those of Anacardium occidentale (Cashew-nut), 
Arachis hypogcea (Pea-nut), Caryocar nuciferum (Butter-nut of 
Guiana), Cassia fistula, Cocos nucifera, Garcinia mangostana (Mango- 
steen), etc., all of which, whether introduced or indigenous, are now 
growing in the New World. The extreme probability of their 
having been derived from ships in the vicinity is pointed out in 
later pages. 

The South-West of England. — Respecting the occurrence of 
West Indian seeds on the beaches of the south-west of England, the 
following remarks may be made. Mr. Hamilton Davey, the author 
of The Flora of Cornwall, tells me that he has often found on the 
Cornish coast between St. Ives and Newquay large seeds which he 
took to be those of Entada scandens, and that he had them sawn through 
for the benefit of his students. It is well known that Gulf Stream 
drift is not infrequently beached on the north coast of Cornwall. 
The Great Western Railway Company, in advertising the climatic 
attractions which the " Cornish Riviera " derives from the Gulf 
Stream, informs the public that " many have been the instances of 
West Indian drift cast upon the shores of St. Ives Bay." 

I noticed a seed of Mucuna urens from Cornwall in the Kew 
Museum. There is also exhibited there a fruit of Sacoglottis amazonica 
gathered on the South Devonshire coast by Mrs. Hubbard in Novem- 
ber 1887. The find of the Sacoglottis fruit by Mrs. Hubbard had an 
important result. The fruit was unknown at Kew, and the requisite 
inquiry instituted by Sir D. Morris, Mr. Hillier, and others led to 
the identification of this and other fruits of the same plant from the 
drift of West Indian beaches, a matter dealt with in the discussion 
on Sacoglottis amazonica. Sir D. Morris, when referring to these 
drift fruits in Nature for November 21, 1895, gives Mrs. Hubbard's 
Devonshire locality as Bigborough Bay. Evidently Bigbury Bay, 
a few miles west of Salcombe, is here meant. 

On April 28, 1909, I found on the beach at Sewer Mill Cove, near 
Salcombe, South Devon, two seeds lying within a few paces of each 
other, both in a sound condition, one of Guilandina bonducella and 
the other of the Mucuna species near M. urens. On January 18, 
and April 2, 1912, I came upon solitary seeds of Entada scandens 
at Moor Sands and at Sewer Mill Cove, beaches lying east and west 
of Salcombe, one of them with the base of a B alarms shell still 
attached. Though in both cases the seeds appeared sound, they 
possessed rattling broken kernels, and neither of them could have 
been germinable. The drift is sometimes carried far up the 
English Channel. Thus a Mucuna seed has been picked up at 
Portsmouth (Hemsley in Chall. Bot., IV., 291), and in the Kew 
Museum there is a seed of the same genus, labelled " near urens" 
which was found at St. Helens in the Isle of Wight. A seed of 
Entada scandens, now in the Kew Museum, was given to me by Miss 
M. Moseley, who found it in 1897 on the beach at Vimereux near 
Boulogne. 

It is noteworthy that my discovery on the south coast of Devon 
of seeds of Entada scandens in the middle of January and early in 



WEST INDIAN DRIFT ON EUROPEAN SHORES 29 



April 1912, corresponds with the drifting into these latitudes from 
the southern waters of the North Atlantic of large quantities of 
Physalia (Portuguese men-of-war) and other pelagic organisms. 
Dr. Orton in Nature, February 27, 1913, observes that during March 
and early April 1912, numbers of Physalia were cast on our shores 
at various points between Cardigan Bay and Seaford in Sussex, 
and that together with Velellce others were washed up at the same 
time on the coasts of France. (With respect to the Velellce a French 
naturalist is cited.) At the end of March 1912 I noticed " Portu- 
guese men-of-war " stranded in quantities on the beaches of South 
Devon between Start Point and Bolt Tail. On showing some of 
them to persons in the habit of crossing Salcombe Harbour daily, 
I learned that these creatures had been recently observed sailing 
up the harbour in small fleets. Their condition on the beaches 
indicated that whilst some had been beached only for a day or two, 
others had been lying there for a week or more. Dr. Orton regards 
this extensive incursion into our latitudes of the surface organisms 
of southern waters as the result of the almost continuous high 
southerly to south-westerly winds in the south-eastern part of the 
North Atlantic in the early part of the year. 

There was a similar invasion of our seas by southern pelagic organ- 
isms in the early part of 1913. Commander Campbell Hepworth, 
in a paper in the Geographical Journal (November and December 
1914), quotes from Dr. Orton's letter in Nature, and adds on the 
authority of Dr. Allen that Physalia occurred on the south coast of 
England in February, March, and April 1913. No West Indian 
drift seeds were noticed by me on the south coast of Devon in this 
connection; but early in January of that year after a long period 
of strong south-westerly winds I found an abundance of the horny 
skeletons of Velellce on a beach near Salcombe. During the first 
two or three days of January 1916 an enormous number of Velellce 
were piled up on the beaches of South Devon, east and west of Sal- 
combe, in the living state. The spectacle was unique. Commander 
Hepworth refers to the occasional presence " especially off the west 
coast of Ireland, but seldom off Devon and Cornwall " of lanthina 
(Violet Sea-snail) and Velella. However, lanthina often came under 
my notice as a boy on the Cornish beaches. The association in this 
paper on the Gulf Stream of the indications of the pelagic organism 
with those of the thermometer and hydrometer endows it with 
special value for the student of dispersal by currents. 

On the beaches of South Devon one occasionally finds Pea-nuts 
(Arachis hypogcea), half-eaten ears of Maize, Coco-nuts, etc., evidently 
thrown over from ships approaching the English Channel, besides 
other fruits and seeds, the origin of which is uncertain. Thus on 
May 16, 1911, two large Sapotaceous seeds, 2 J inches in length, 
were picked up by me on Rickham and Moor Sands beaches near 
Salcombe. Dr. Rendle tells me that a specimen sent to him pre- 
sumably belonged to Lucuma, the species being doubtful. From 
a comparison with seeds in my collection of Lucuma mammosa, the 
familiar Mammee-Sapota of the West Indies, it is evident that the 
drift seeds do not belong to that species, though similar in size. 



30 PLANTS, SEEDS, AND CURRENTS 



Then again on November 17, 1914, I found washed up on Rickham 
beach a nearly entire fruit of Passiflora and a portion of a second 
fruit. The seeds of both were dead. On January 11, 1916, I picked 
up on the same beach another entire fruit of the same species of 
Passiflora, containing sound seeds from which I am now raising 
healthy seedlings. It was lying amongst the dead Velellce that 
had been thrown up in such quantities a few days before, and 
doubtless arrived with them. The fruits reminded me of the 
Water Lemon of Jamaica (P. laurifolia); but since Passifloras 
are cultivated in England, and some grow almost wild in Ireland 
and in the south-west of England, we can scarcely look to the 
West Indies for the source of these drift fruits. Further details 
will be found given in connection with Passiflora in the Turks 
Islands. 

The South Coast of Wales. — West Indian drift seeds and fruits 
are sometimes carried into the Bristol Channel and stranded on the 
Welsh coasts. Several years ago Dr. A. Lloydd-Jones sent to Kew 
a seed of Entada scandens, " said to be exactly like one picked up 
in Swansea Bay" (Kew Bulletin, 1893, p. 114). On these coasts, 
as on the shores of the English Channel, the buoyant portions of 
edible tropical fruits thrown over from passing ships must often 
be cast up on the beaches, and allusion has above been made to this 
point with respect to the south coast of Devon. Thus in the Kew 
Museum there is a perfect specimen of a Mango-stone (Mangifera 
indica) from the coast of South Wales, which was probably thus 
derived. As is shown in a later page, empty Mango-stones are of 
common occurrence on West Indian beaches and elsewhere. There 
is also in the drift collection of the Kew Museum a fruit from South 
Wales which is labelled Caryocar nuciferum, the " butter-nut " of 
British Guiana, sometimes imported into Great Britain. 

The West Coast of Ireland. — It is shown in the next chapter 
that much of the bottle-drift which reaches the shores of the United 
Kingdom from the seas of the West Indies, Florida, and the South- 
eastern United States is stranded on the west side of Ireland. This 
fact would lead us to expect that the Irish coasts would receive the 
bulk of the West Indian seed-drift thrown up on our shores. But 
I gather that though often found it has rarely been recorded. The 
principal fact usually cited is that given by Sir Hans Sloane in his 
book on the West Indies (II., 41) and in his paper in the Philosophical 
Transactions (Vol. XIX.), which were written more than two centuries 
ago. He there alludes to seeds of the " ash-coloured Nickar " and of 
the " Cocoon " found on these coasts. There can be no doubt that the 
seeds of Guilandina bonducella and Entada scandens are here indicated. 
From a drawing made of a plant raised from a seed picked up on 
the west coast of Ireland Robert Brown determined the species to 
be Guilandina bonduc (Hemsley in Chall. Bot, IV., 277). Since, 
however, the seeds of this species are not as a rule buoyant in the 
West Indies and are not a frequent constituent of West Indian 
beach-drift, it is more probable that the seeds in question belonged 
to the allied species, G. bonducella, the seeds of which have been 
found in almost every European locality where West Indian drift 



WEST INDIAN DRIFT ON EUROPEAN SHORES 31 



has been observed. For further details on this point Note 9 of the 
Appendix should be consulted. 

Through the courtesy of Mr. Lloyd Praeger I have received whilst 
preparing this work some more particulars about West Indian seeds 
on the western sea-borders of Ireland. The following extract is 
from a letter of April 29, 1915, written to him by Miss M. C. Knowles 
of the National Museum, Dublin : 44 On p. 133, Irish Naturalist 
for 1897, I see Mucuna urens was picked up on the shores of Kilkee 
(Co. Clare). Mr. Tomlinson sent me Entada scandens that he had 
found on the north coast a short time ago, but he did not give me 
the locality. I have found it at White Park Bay (Co. Antrim) on 
several occasions." 

On September 2, 1915, Miss Knowles wrote to tell me of two 
seeds, Entada scandens and Mucuna sp., just brought to her, which 
were found by the Rev. Br. S. O'Connell in a cave at Kilkee. They 
were sent to me for inspection by the Rev. Br. M. A. Hoban. Both 
of them appeared to be sound and germinable. The Mucuna seed 
came nearest to those of M. urens. I may add that with the object 
of directing interest to this matter I sent in May 1915 to the National 
Museum, Dublin, a collection of West Indian drift seeds most likely 
to be found on the Irish coasts. 

The West Coast of Scotland and the Hebrides. — As already 
observed, Sir Robert Sibbald in his Scotia Illustrata (II., lib. 4, p. 55, 
1694) includes, without commenting on their origin, Phaseoli Molucani 
and Nux Indica in a catalogue of marine plants and other things 
44 quae in Mari proveniunt." The use of the name Molucca Beans has 
been before explained. The Indian Nut, 44 of which snuff-boxes 
are made," is evidently Entada scandens, and is thus regarded by 
Sloane, who identifies it in his paper in the Philosophical Transactions 
with the Cocoon, which is its native name in Jamaica. Amongst 
the West Indian seed-drift stranded on the north-west coasts of 
Scotland and on the Hebrides, and described by Sloane in his Voyage 
to Jamaica, etc. (II., 41, 186), are represented Guilandina bonducella, 
Sacoglottis amazonica, and Manicaria saccifera. The first named 
can be at once recognised from his account. As regards the other 
two species, the identification of the Manicaria fruits was made by 
Plukenet ; whilst the description of the Sacoglottis fruits, as quoted 
by me under that head, leaves no room for doubt as to their identity. 

We have before referred to the account which Martin gives in 
his Description of the Western Islands of Scotland (1703) of the 
medicinal uses to which the Hebrideans and the people of Mull put 
the Molucca Beans and Indian Nuts washed up on their shores, 
and we have dwelt also on his account of the superstitions attached 
to them. Amongst the seeds he mentions we can recognise those 
of Entada scandens and Guilandina bonducella. He adds (p. 283) 
that the Steward of St. Kilda told him that they had found Molucca 
Beans in a nest of the Solan Goose, it being the habit of these birds 
to carry to their nests many things they find afloat in the sea. This 
is interesting in connection with the discovery by Sir William Milner 
of large West Indian seeds in the crops of nestling petrels at St. 
Kilda, a matter which drew the attention of Darwin, and is treated 



32 PLANTS, SEEDS, AND CURRENTS 



in Note 59 of my work on Plant Dispersal. Mr. Charles Dixon in 
Ibis (1885) refers to Sir W. Milner's observation in the case of the 
Fulmar Petrel and speaks of them as Brazilian seeds brought by the 
Gulf Stream, adding that he himself found a specimen in the crop 
of one of these birds in the same locality. Sir W. Milner, it appears, 
procured several of these seeds from the crops of the birds, and 
Mr. Dixon says that the natives of the island find them at times. 
The reference by Darwin is made in letters to Hooker in 1859 (Life 
and Letters, 1888, II., 147-8). He remarks on the curious fact of 
" petrels at St. Kilda apparently being fed by seeds raised in the 
West Indies." Unfortunately the seeds were never identified, and 
more than forty years afterwards, when Mr. Hemsley applied to Sir 
Joseph Hooker for particulars, too long an interval has elapsed for 
the determination of this point. The West Indian drift seeds carried 
to our islands that would be most likely to be swallowed by sea-birds 
would be those of Guilandina bonducella. When in the Keeling 
Islands I was informed by residents that the seeds of this plant, 
which grows on the islands, are sometimes found in the stomachs 
of sea-birds, such a frigate-birds and boobies. 

Pennant in his Voyage to the Hebrides in 1772 (I., 266) refers to 
" the nuts commonly called Molucca Beans which are frequently 
found on the western shores of the Hebrides." He is one of the 
first to employ the Linnean designations in naming the seeds stranded 
on the Western Islands of Scotland, and his list comprises Dolichos 
(Mucuna) urens, Guilandina bonduc, G. bonducella, and Mimosa 
(Entada) scandens, all, as was long before pointed out by Sloane, 
natives of Jamaica. He adds C. Bauhin's description, derived 
from Clusius, of a fifth kind, which is evidently the composite seed 
of Ipomcea tuberosa, and special reference to it in this connection 
will be made when dealing with that species. There is in the Kew 
Museum another drift seed of the same species of Ipomoea from 
the Hebrides, which was obtained by Colonel Fielden about 1891. 

A well-known Genevese naturalist, Necker de Saussure, made a 
long sojourn in the Hebrides between 1806 and 1808. Speaking 
of the " American " seeds, Dolichos (Mucuna) urens and Mimosa 
(Entada) scandens, which had been thrown up by the waves, he says 
that when traversing South Uist he observed them in every cottage 
(Voyage en ticosse et aux lies Hebrides, 1821, III., 22). There are 
doubtless numerous references in modern works to the West Indian 
seeds transported to these islands. For instance, Mr. C. V. Peel 
in his Wild Sport in the Outer Hebrides, 1901, mentions the seeds 
of the two species just named as occurring with much other Atlantic 
drift on the west coast of North Uist. 

The Orkney Islands. — These islands are of special interest in 
the story of this investigation, since the stranded " Molucca Beans " 
(as they were called), which were figured by the two Wallaces, the 
early historians of the group, were in most cases identified by Sloane 
with seeds familiar to him in Jamaica (Phil. Trans. 1695-7). Stand- 
ing thus on firm ground when he surmised that the seeds had been 
brought by the sea from the West Indies, Sloane forestalled by 
quite two generations the Norwegian observers of the middle of 



WEST INDIAN DRIFT ON EUROPEAN SHORES 33 



the eighteenth century. Yet, as before remarked, even Sloane 
must in this respect give way in point of priority by at least a 
quarter of a century to Debes (1670) and his informant, the " very 
knowing man," who regarded the strange seeds stranded on the 
Faroe Islands as " brought hither by the Stream " from the West 
Indies. 

But to return to the Wallaces, I examined the three editions of 
this early description of the Orkney Islands that are in the British 
Museum library. The first, " A Description of the Isles of Orkney 
by Master James Wallace, late minister of Kirkwall, published after 
his Death by his Son " was issued at Edinburgh in 1693. It was 
written about 1688 at the instigation of Sir Robert Sibbald, Geogra- 
pher to Charles II. Under the head of substances cast up by the 
sea he alludes (p. 14) to the frequent occurrence of " these pretty 
Nuts (named Molluca Beans in the margin) of which they use to 
make Snuff-Boxes. There are four sorts of them (he adds) the 
figures of which are set down." In the plate under the name of 
" Molocca Beans " are figured the seeds of Entada scandens, a 
species of Mucuna, probably M. urens, a species of Erythrina, and 
Ipomoea tuberosa. 

Though written without any mention of his father's book, An 
Account of the Islands of Orkney by James Wallace, M.D., F.R.S. 
(London, 1700), is evidently an enlarged edition of the previous 
work. With access to Sloane' s paper in the Philosophical Transactions 
(1695-7), which his father could not have had, the author thus 
writes (p. 36) : 44 After storms of Westerly Wind, amongst the 
Sea- Weed they find commonly in places exposed to the Western 
Ocean these Phaseoli that, I know not for what reason, go under 
the name of Molucca Beans. The ingenious Doctor Sloan in the 
Philosophical Transactions, Number 222, gives a very satisfactory 
account, how from the West Indies, where they commonly grow, 
they may be thrown in on Ireland, the Western parts of Scotland, 
and Orkney. You have the figures of four different sorts of them." 
However, in his plate there is a fifth figure of 44 another molucca bean " 
which is certainly Guilandina bonducella. The drawing of the seed 
of Entada scandens is here enlarged to natural size, and in the place 
of his father's figure of a Mucuna seed there is a drawing of a Dioclea 
seed. The other seed-figures, one of an Erythrina species and the 
other of Ipomoea tuberosa, are unchanged. 

The third edition, which is entitled " A Description of the Isles of 
Orkney by the Rev. James Wallace, reprinted from the edition of 
1693 and with additions by the Author's son in the edition of 1700," 
was edited by John Small and published at Edinburgh in 1883. 
This work contains both the plates of the seed-drawings of the two 
earlier editions. It may here be remarked that an additional reference 
to the occurrence of the seeds of Ipomoea tuberosa on the Orkney 
beaches at the close of the seventeenth century is made by Petiver, 
of which further mention will be made. 

The next important reference to seeds of West Indian beach-drift 
on the coasts of these islands is to be found in 44 An Account of four 
sorts of strange beans, frequently cast on shoar on the Orkney Isles, 



34 PLANTS, SEEDS, AND CURRENTS 



with some conjectures about the way of their being brought thither 
from Jamaica, where three sorts of them grow " by Sir Hans Sloane 
(Phil. Trans. 1695-7). After referring to the mention of them by 
Sibbald and the elder Wallace, he deals with them successively. 
The first he identifies with the Jamaican " Cocoon," the name given 
in that island to the seed of Entada scandens, as known to botanists. 
The second, he says, is the Jamaican " Horse-eye bean," which from 
his description is evidently the seed of Mucuna urens, a seed that 
bears the same popular name in our own time. The third, he says, 
is the " ash-coloured Nickar " of Jamaica, called so, as he goes on 
to state, from its being " very like a Nickar," such as boys play 
with. I may add that " knicker," " nicker," etc., were forms of 
an old English and Scottish name for marbles. Botanists have no 
hesitation in recognising here the seeds of Guilandina bonducella. It 
bears the same common name in the West Indies now. Of the source 
of the fourth he states that " authors are silent " ; but although 
he remarks that he " had never seen it grow," his reference to it 
as described and figured by Clusius, the elder Wallace, and others, 
undoubtedly points to its being the seed of Ipomcea tuberosa, as 
determined in recent years by Mr. Hemsley, and to which further 
allusion will be made. I have not come upon any recent 
references to West Indian drift seeds in the Orkney Islands, but one 
may note that Mr. Bullock, the naturalist, gathered seeds of Entada 
scandens there about a century ago (A. de Capell Brooke in Travels 
in Sweden, etc., in 1820, p. 317). 

The Shetland Islands. — In connection with the occurrence of 
West Indian seed-drift in this archipelago I put myself in communica- 
tion with Mr. John Fox, then stationed in that group, and through 
his kindness was able to inspect two seeds from the Shetland beaches, 
one of Entada scandens, the other of Dioclea refleuca, both of them in 
sound condition, which were courteously loaned by Mr. J. Tulloch 
of Lerwick. Mr. Fox subsequently sent me two seeds of Entada 
scandens, one of the species of Mucuna near M. urens, and a seed of 
Ipomcea tuberosa, the last being the species above named as found 
on the Orkney beaches, and it is one that is represented in my drift 
collections from Jamaica and the southern extremity of the Bahamas. 
All these seeds were picked up on the Shetland coasts, and Mr. Fox 
tells me that the wives of the fishermen make ornaments of them. 
In reply to a letter asking for further information, Mr. Tulloch kindly 
furnished me with references to Shetland literature, but added that 
he knew of no mention there of Gulf Stream drift. At his suggestion 
I wrote to Mr. Peterson, postmaster of Foula, an island at the south- 
west corner of the group ; but on doing so I learned that that island 
is not suited for retaining drift, and that during a residence of over 
fifty years Mr. Peterson had never seen any of the seeds described 
to him by me. 

The Faroe Islands. — The occurrence of these strange drift 
seeds on the Faroe Islands formed a subject of remark for Peter 
Claussen in his Description of Norway, which was written at the close 
of the sixteenth or the beginning of the seventeenth century; but, 
as previously stated, he had no idea of their true nature. Debes, 



WEST INDIAN DRIFT ON EUROPEAN SHORES 35 



who wrote the preface of his book on these islands in 1670, has been 
already mentioned in connection with the drift seeds. It was, 
however, with those of Entada scandens as found on the Faroe 
beaches that he was especially concerned, and from his description 
of them there can be no doubt as to their specific identity. 

In 1817 H. C. Lyngbye, a Danish algologist, visited the Faroes, 
and in his Tentamen Hydrophytologiae Danicce of 1819 he remarks 
(p. 60) that he picked up on the shores seeds of Mimosa scandentis 
(Entada scandens), Dolichos mentis {Mucuna urens), and Guilandina 
bonducella. In recent years Ostenfeld and Borgesen have again 
directed attention to the West Indian seeds and fruits washed up 
on these islands, and they mention those of Cocos, Guilandina, and 
Entada scandens as coming under their notice {Botany of the Faeroes, 
pp. 116, 812 : Copenhagen, 1901-8). 

Iceland and Greenland. — Seeds and fruits and drift-wood 
from the New World are stranded on the shores of Iceland and Green- 
land, as we learn from the Danish navigator, Admiral von Lowenorn 
(1786), and from Barrow (1817), Sartorius von Waltershausen (1847), 
Irminger (1854), and others. In his Physical Geography (1873, 
p. 206) Laughton quotes from the report of the United Coast Survey 
for 1860, to the effect that drift from the West Indian islands is 
stranded in very considerable quantities on the south coast of 
Iceland, where, " on the beach under Snaefell, trees with their 
roots, and scraps of bark, logs of mahogany, and seeds which grow 
in Jamaica at the nearest, roll in the surf." We learn from Irminger 
(Zeitsch. f. Allg. Erdk., III., 187-90, 1854) that " many kinds of 
Mimosas (t. e. seeds) are to be found on the coasts of Norway, Faroes, 
Iceland, and Greenland, and also drift-wood." Von Waltershausen 
in his work on the physical geography of Iceland (p. 347) refers to, 
without naming, the tropical seeds and fruits thrown up with much 
drift-timber on the coasts. With respect to Greenland Laughton 
(p. 249) quotes Irminger to the effect that " beans of Mexican growth 
are often washed up on the Greenland shores " ; and Kohl observes 
(p. 160) that in the southern Danish settlements of Greenland on 
the shores of Davis Strait every one knows the seeds of Entada 
scandens, which are often cast up by the waves. 

The Scandinavian Coasts. — The West Indian drift thrown up 
on the Norwegian coast has been several times mentioned in previous 
pages. Claussen and Worm in the seventeenth century and many 
others in the eighteenth century, such as Gunnerus, Pontoppidan, 
Strom, Tonning, etc., interested themselves in the matter. In the 
early part of the nineteenth century Wahlenberg, the Swedish 
naturalist, in his Flora Lapponica (1812, p. 506) referred to the seeds 
of Mimosa scandentis {Entada scandens) and Dolichos urentis {Mucuna 
urens) as washed up on the north and north-west coasts of Norway. 
A few years after, A. de Capell Brooke in the account in his Travels 
through Sweden, Norway, and Finmark to the North Cape in 1820 
(pp. 295, 317, 318) alluded to the drift from the New World cast up 
on the Norwegian coasts. On the Tromsoe and Rost coasts much 
timber was found, including baulks of Honduras mahogany. Seeds 
of Entada scandens are (he says) thrown up after great storms. 



36 PLANTS, SEEDS, AND CURRENTS 



Mr. Bullock, the naturalist, who had himself picked them up on the 
Orkneys, identified the seeds. 

In recent times we have Lindman and Sernander. The last 
named deals especially with the subject in his Den Skandinaviska 
Vegetationens Spridningsbiologi (Upsala, 1901, p. 116, etc.); and the 
results obtained by Lindman and his predecessors, including the 
Linnean botanists, are there discussed under the name of " Gulf 
Stream products." Lindman made a comprehensive study of the 
subject in 1880. It appears that the coasts northward from Sond- 
more to Lofoten and Tromsoe receive most of the West Indian seed- 
drift. But it reaches as far north as the vicinity of the North Cape, 
and may even, as Robert has shown, double that promontory and 
enter the White Sea. To the south it extends to the Swedish and 
Danish coasts, and it is found on the shores of the Baltic Sea. The 
seeds of most frequent occurrence are those of Entada scandens, 
Guilandina bonducella, and Mucuna urens. In the first two cases 
Lindman procured the germination of the seeds. Those of Entada 
scandens have even been found in a subfossil condition in the peat- 
bogs of Tjorn on the south-west coast of Sweden, having been 
originally stranded in post-glacial times on a beach in that locality. 

A word may be said here on the doubling of the North Cape by 
West Indian seed-drift. That the seeds reach the extreme north 
was long ago mentioned by Wahlenberg in the work quoted above, 
where he refers to them as washed up on the Finmark coast. Robert, 
the French naturalist, who was in this region in 1835-6, states that 
his companions found the seed of Mimosa (Entada) scandens on the 
island of Mageroe, on which the North Cape lies. Lottin, he says, 
picked up a seed of the same plant near the same promontory in 
" Laponie " (Lapland), which would indicate a locality to the east 
of the cape. Robert himself found the same seed on the shores of 
the White Sea. Gumprecht, Fogh, Vibe, and others allude to these 
interesting discoveries, the references to which are given at the close 
of the chapter. 

Amongst the stranded drift named in Sernander' s list are the fruits 
of Anacardium occidentale, Cassia fistula, Cocos nucifera, Garcinia 
rnangostana (Mangosteen), Lagenaria vulgaris, etc. The Mangosteen 
fruit was found by Lindman in 1879 cast up on one of the Lofoten 
Islands, and was doubtless thrown over from a ship in the vicinity. 
The two first named have not been found since the time of Gunnerus 
and Strom in the middle of the eighteenth century ; and, as indicated 
in later pages, their West Indian origin as components of Scandina- 
vian beach-drift is improbable. Gourds and calabashes, sometimes 
" worked," have been known to be stranded from time to time on 
the coasts of Norway ever since the days of Gunnerus and Strom. 
In the discussion of Crescentia it is stated that there are grounds for 
the belief that some of these gourds of Norwegian beach-drift belong 
to this genus. Crescentia gourds are in common use in the West 
Indies, and form a characteristic feature of the drift on West Indian 
beaches, the tree (C. cujete) being a native of that region. Lagenaria 
gourds most probably reached the coasts of Norway from passing 
vessels. Coco-nuts have been picked up on Norwegian beaches 



WEST INDIAN DRIFT ON EUROPEAN SHORES 37 



since the middle of the eighteenth century. They were mentioned 
by Strom, Tonning, and Linnaeus; and Sernander observes that 
they are generally more or less injured. When at Trinidad some 
years ago the present writer was informed by Dr. Fredholm that in 
1885 he found three coco-nuts within a space of a hundred yards 
on a beach of one of the Lofoten Islands, evidently derived from a 
wrecked or a passing ship. 

There must be numerous references in Danish literature to West 
Indian seed-drift on the western coasts of Denmark. In Petermann's 
Mittheilungen for 1877 (XXIII., 316) mention is made of an interesting 
note by Prof. Erslev on the occurrence there of seeds of Entada 
scandens and other tropical products which have been brought by 
marine currents to the shores of Jutland (see the list of works quoted 
at the end of the chapter). 

The Azores.— The occurrence of West Indian seeds on the beaches 
of the Azores has long been known. Darwin, who was especially 
interested in the subject, obtained a number of seeds of Entada 
scandens and Mucuna urens from these islands and sent them to 
Hooker at Kew, who referred to the matter in his lecture on " Insular 
Floras " delivered before the British Association in 1866 (reprint of 
1896, pp. 15, 28 ; see also Hemsley's Chall. Bot., IV., 291). Speaking 
of the Azores, Hooker remarked that " the large Bean-like seeds of 
Entada, a West Indian climber, are thrown up abundantly on the 
islands by the Gulf Stream, but never grow into plants, if indeed they 
ever germinate on their shores." These seeds were sown at Kew, 
and " many germinated and grew to be fine plants, showing that 
their immersion during a voyage of nearly 3000 miles had not affected 
their vitality." (The Mucuna seeds are mentioned by Hemsley 
as above quoted.) 

During my sojourns on the Azores, especially on the north coasts 
of San Miguel and at the western end of Pico, I paid much attention 
to this point and obtained the following results. The drift seeds 
are familiar to the people of the coast towns and villages, and are 
as often picked up whilst floating off the shores by the fishermen 
as they are gathered by the children on the scanty beaches. When 
the purpose of my visit became known in any coast town or village 
I was usually supplied with several specimens of Entada scandens 
and of the two species of Mucuna (M. urens and an allied species) 
represented in European beach-drift. Other drift seeds and fruits 
are often overlooked or disregarded. Amongst them would be 
the seeds of Guilandina bonducella. On my displaying a specimen 
to the people of Magdalena at the west end of Pico they soon brought 
me a seed which had been found on the beach. The seeds were 
nearly always sound. 

I searched several beaches and picked up the following fruits 
and seeds : two sound seeds of Sapindus saponaria, one at Magdalena 
and the other at Porto Pym (Fayal) ; an empty fruit of Astrocaryum 
near Magdalena; and a woody fruit, probably belonging to the 
Juglandea?, on San Miguel. The more conspicuous seeds of Entada 
and Mucuna are soon found on the beaches by the inhabitants. 
The seeds of Sapindus saponaria are particularly interesting, since, 



88 PLANTS, SEEDS, AND CURRENTS 



as far as I know, they have not been recorded from European 
beaches. They are characteristic of West Indian beach-drift, and 
have been known to germinate in the Bermudas after having been 
brought there by the Gulf Stream. 

The complete list of West Indian drift seeds and fruits known to 
me as stranded on the Azores would be as follows : — 

Entada scandens. 
Mucuna urens 
Mucuna near M. urens. 
Guilandina bonducella 
Sapindus saponaria. 
Astrocaryum (Palmacece). 

Note. — Of these the first four have been recorded from European 
beaches. As in Europe, of the two kinds of Mucuna seeds that of 
the true M. urens is least common, two-thirds of the seeds belonging 
to the allied species and one-third to M. urens proper. The 
fruit of Juglandece, being of doubtful origin, has not been included 
in the list. 

It is highly probable that these seeds reached the Azores from the 
West Indies by the circuitous Gulf Stream route. The intervention 
of the Sargasso Sea (20°-35° N. lat. and 40°-70° W. long.), where 
there is little or no surface circulation, bars the direct route from the 
West Indian region. As indicated by the bottle-drift data dealt 
with in Note 12 of the Appendix, this seed-drift must have been at 
first carried northward past Cape Hatteras towards the Nova 
Scotian and Newfoundland coasts, which would involve a tedious 
drifting passage of at least a year's duration. 

Amongst the other constituents of Azorean beach-drift are lanthina 
shells, Portuguese men-of-war (Physalia), a little dead Sargasso 
weed, and pumice, the last often abundant, and as shown in Note 23 in 
great part of local origin. The Sargasso question is treated in Note 
29 of the Appendix ; but it may be here stated that living specimens 
did not come under my notice on the Azores beaches, the dead 
fragments, which are well incrusted with polyzoa, having been 
derived, not directly from the Sargasso Sea to the south-west, but 
by the circuitous route to the northward, past Cape Hatteras, which 
is taken by the West Indian seed-drift. 

The Canary Islands and Madeira. — The writer has come upon 
no record of West Indian seeds stranded on these islands ; but from 
the indications of bottle-drift discussed in Notes 27 and 28 of the 
Appendix it is evident that seeds from the tropics of the New World 
must be at times carried there. Although he spent several days 
in examining the north coasts of Teneriffe, no seed-drift that he 
could recognise as hailing from the New World came under his 
notice. The shores of this island are as a rule not well suited for 
catching drift; but there are localities, as in the cases of beaches 
east of Orotava and on the east side of Point Hidalgo, where a con- 
siderable amount of oceanic drift is cast up, as shown in the abundance 
of Spirula shells, Portuguese men-of-war (Physalia), etc. It may 



WEST INDIAN DRIFT ON EUROPEAN SHORES 39 



be added here that Mr. Samler Brown in his Guide to Madeira 
and the Canary Islands (8th edit., 1905) deals with many kindred 
matters, but says nothing of the stranding of West Indian seeds. 

The Risks of Premature Generalisations on the Dispersal 
of Seeds by the Great Oceanic Currents. — The discussion to 
which this chapter has been devoted opens up a number of other 
questions; and perhaps the one that will first present itself is that 
connected with the path followed by the floating seed in its traverse 
of the Atlantic. Without a fairly precise acquaintance with the 
working of the currents in this direction it is hazardous to generalise 
on the subject, and to indulge in a picturesque description of the 
currents at work in distributing seeds. 

The floating seed can tell its own story, but in a very imperfect 
fashion. It can tell us nothing of its route and often nothing of 
the duration of its ocean traverse; and although we should be 
usually right in assuming that a tropical seed found on European 
beaches came from the West Indies, it would not follow that it grew 
in that region. There would be possibilities that it came originally 
from the shores of the Spanish Main, or from the estuary of the 
Amazon, or even from the mouth of the Niger, before it came within 
the influence of the Gulf Stream in the Florida Sea. Nor could we 
read its history in its specific name, since the great majority of 
tropical seeds transported by the currents belong to littoral and 
estuarine plants common to both the African and the American 
sides of the tropical Atlantic, and under such circumstances any 
discrimination as to source would be hazardous. 

The need thus presents itself of looking elsewhere for evidence 
to supply what is lacking in the testimony of the drifting seed, and 
in our need we appeal in the following chapter to the evidence of 
bottle-drift. This is all the more requisite since some of the state- 
ments one reads concerning the agency of currents in dispersing seeds 
require considerable qualifications and illustrate the necessity of 
exact knowledge of the principles regulating the process. Thus in 
the English form by Prof. Ains worth Davis of Pouchet's VUnivers 
(1906, p. 394) Dr. Karl Muller in Les Merveilles du Monde Vegetal 
is thus quoted : " The great current which springs from the eastern 
coast of South America has been known to bear a flotilla of thirteen 
species of plants from Brazil and Guiana to the shores of Congo 
in Africa. . . . Another grand oceanic current, traversing an immense 
space of the torrid zone, constantly transports fruits from the shores 
of India, which its waves tumultuously scatter on the rocks of 
Brazil." 

With regard to these currents it is not apparent what the writer 
could have intended, since the great equatorial currents could only 
carry materials from the Congo to Brazil, whilst there is no great 
oceanic current that constantly transports Indian drift to Brazil. 
It is true that a bottle has been known to reach the Brazilian shores 
from off the coast of Natal, and that drift from the Indian Ocean 
can at times find its way into the South Atlantic in a small branch 
of the Agulhas Current that doubles the Cape, instead of being 



40 PLANTS, SEEDS, AND CURRENTS 



deflected eastward with the main stream; but it would certainly 
be erroneous to speak of a grand oceanic current establishing constant 
communication between India and Brazil. On a later page attention 
is called to a serious blunder by which a bottle is made to reach 
India from the tropical Atlantic instead of from the mouth of the 
Red Sea, through a confusion between east and west longitude. In 
this case fortunately the published record itself supplied the refuta- 
tion; but this would not always be possible, especially in cases 
where the supposed fact is quoted without the data. 

Transport of Mahogany Logs to the Coasts of Greenland, 
Iceland, and the North- West of Europe . — It is to be expected 
that seed-drift from the tropics of the New World would be some- 
times accompanied by trunks of trees from the same region. Gum- 
precht (p. 430) mentions that Lowenorn, the Danish admiral, found 
logs of mahogany in 1786 on the east coast of Greenland; and he 
adds that trunks of the same tree are thrown up on the west coast 
near the island of Disco. In the last case the wood was in such good 
condition that the Danish governor had a table made of it. I have 
already referred to Laughton's quotation from the report of the 
United States Coast Survey for 1860 that mahogany logs are rolled 
in on the coast of Iceland. Lyngbye avers in his Tentamen Hydro- 
phytologice Danicce, 1819, that he saw on the Faroe Islands a portion 
of a canoe made of mahogany. Gumprecht (p. 426) and Kohl (p. 159) 
refer to Irminger's observation of masses of drift-wood on the west 
side of the Faroe Islands. Drift-timber is also cast ashore on the 
Shetland Islands^which may hail from the tropics of the New World. 
Mr. Fox sent me a piece of cedar( ?) which was chopped from a baulk 
about twenty-five feet long. It was honeycombed by the borings 
of the Teredo, and was stranded on the west coast. We learn from 
De Capell Brooke (p. 295) that much timber is beached on the 
Norwegian sea border in the Tromsoe district and on Rost, and he 
particularises Honduras mahogany. One may note in this connection 
Pennant's statement that " part of the mast of the Tilbury man-of- 
war, burnt at Jamaica, was taken up on the Western Coast of 
Scotland " (A Voyage to the Hebrides in 1772). 

Living Turtles carried by the Gulf Stream to the 
Hebrides, the Orkneys, and the Shetlands. — This matter has 
already been incidentally alluded to. Pennant in his Voyage to 
the Hebrides in 1772 observes that " American tortoises, or turtle, 
have more than once been taken alive on these coasts, tempest- 
driven from their warm seas." Necker de Saussure in his paper in 
the Bibliothique Britannique (1809), as quoted by Gumprecht (p. 416), 
also mentions the stranding of turtles in connection with his sojourn 
in this group. Mr. Peel in his book Wild Sport in the Outer Hebrides, 
1901 (p. 3), tells us that young turtles together with West Indian 
seed-drift are washed up on the shores of those islands. The Rev. 
James Wallace, writing of the Orkney Islands at the close of the 
seventeenth century, states that " sometimes they find living Tor- 
toises on the shore " (1883 edition, p. 17). Some particulars of the 
discovery of one of these turtles in the Shetlands are given by the 
Rev. John Brand in his Brief Description of Orkney, Zetland, etc." 



WEST INDIAN DRIFT ON EUROPEAN SHORES 41 



(Edinb. 1701, p. 174 of the 1883 edition). It appears that a specimen, 
only about a foot in length, was " found alive upon the sand in an 
ebb " in the parish of Northmevan on the shore of Urie Firth. The 
occurrence is characterised as a very rare event. From the remarks 
of Mr. Peel and Mr. Brand it would seem that the turtles stranded 
on the coasts of the Hebrides and the Shetlands are usually young 
specimens. Turtles are often carried north from the Florida 
Straits by the Gulf Stream. On one occasion the writer was on 
board a steamer, bound north from the Bahamas to Philadelphia, 
which, shortly after passing the Hatteras Lightship in 36° N. lat., 
nearly ran down a large turtle. It raised its head as if in astonish- 
ment, and as it swept past the ship's side it was noticed that numerous 
large Balani had established themselves on its back. 

It may be here added that in the London Times for June 19, 
1916, allusion is made to a large turtle, weighing nearly a ton, which 
was taken alive a few days previously in a net off Scilly. In the 
same net was captured a thresher-shark, nearly 12 feet in length, a 
species frequenting the seas of temperate latitudes. The turtle, if of 
West Indian origin, should have been accompanied by seed-drift 
from that region ; but the writer has not since found any drift from 
warm seas on the South Devon coast. (September 9, 1916. The 
turtle proved to be the Leathery Turtle which breeds in the Danish 
West Indies.) 

Summary 

1. In order to give point and method to the author's observations 
on the dispersal of plants by currents in the West Indian region, 
as illustrated by the examination of the beach-drift and by various 
buoyancy experiments, the discussion is at first allowed to centre 
around the fact that some of the materials reach the shores of Europe. 

2. The literature of the subject goes back to the time of Clusius, 
who first figured some of the fruits and seeds in his Exoticorum 
Libri of 1605. Amongst those who interested themselves in the 
matter, down to the close of the eighteenth century, were Peter 
Claussen, the Norse writer (1632); Provost Debes in the case of the 
Faroe Islands (1673) ; Petiver, the laborious compiler of the Gazo- 
phylacium Naturce (1695); Sir Hans Sloane (1695-7); the two 
Wallaces in the case of the Orkney Islands (1693 and 1700); Martin 
in that of the Hebrides (1703) ; Pontoppidan, Bishop of Bergen (1751) ; 
Gunnerus, Bishop of Trondhjem (1765); Strom, the Norwegian 
naturalist (1766); Tonning, the pupil of Linnaeus (1768), and 
Pennant in the case of the Hebrides (1790). Amongst the numerous 
writers of the nineteenth century who have treated the subject in 
more or less detail are Humboldt (1807) ; Necker de Saussure, who 
sojourned in the Hebrides between 1806 and 1808; Sartorius von 
Waltershausen in the case of Iceland (1847); Irminger, famous 
for his investigations of the currents of the North Atlantic (1854); 
Gumprecht, whose paper on the drift-products of the North Atlantic 
(1854) is invaluable to all students of the subject ; Fogh in his paper 
on the Gulf Stream (Copenhagen, 1857) ; Vibe, chief of the Norwegian 



42 PLANTS, SEEDS, AND CURRENTS 



General Staff Survey (1859-61); and Kohl in his history of the 
Gulf Stream (Bremen, 1868). Among those who have specially 
dealt with the botanical side of the subject in recent years are Lindman 
(1883); Hemsley (1885) ; and Sernander (1901). The years named 
refer to the date of the publication concerned, usually the earliest 
when there is more than one (pp. 20-23). 

3. Reference is then made to the popular names in Europe of the 
West Indian drift seeds and to the superstitions connected with 
them. One of the earliest designations was " Molucca Beans, 5 ' a 
name applied in Scotland and in the neighbouring islands (pp. 23-25). 

4. A list is given of the twelve characteristic West Indian seeds 
and fruits that have been recorded, as far as is known to the writer, 
from European beaches and from the Azores, the localities being 
tabulated (pp. 26, 27). The plants supplying them are in half the 
cases leguminous. Those most frequently represented are Entada 
scandens, Mucuna urens, and Guilandina bonducella. Amongst the 
most interesting are Sacoglottis amazonica and Ipomcea tuberosa 
(pp. 26, 27.) 

5. The records of West Indian drift seeds and fruits on the eastern 
side of the North Atlantic, as far as they are known to the writer, 
are then described under the headings of localities : the south-west 
of England (p. 28); the south coast of Wales (p. 30); the west 
coast of Ireland (p. 30) ; the west coast of Scotland and the Hebrides 
(p. 31); the Orkney Islands (p. 32); the Shetland Islands (p. 34); 
the Faroe Islands (p. 34) ; Iceland and Greenland (p. 35) ; the Scan- 
dinavian coasts (p. 35), mention being made of the doubling of 
the North Cape by seeds of Entada scandens (p. 36); the Azores, 
four of the six kinds of seeds and fruits found here being recorded 
from European beaches (p. 37); the Canary Islands and Madeira, 
reference being made to the fact that although the writer has not 
come upon any record of the occurrence of West Indian drift on these 
islands the indications of bottle-drift point to its probability (p. 38). 

6. The risks of premature generalisations on the dispersal of seeds 
by the great ocean currents are then dwelt on, and a particular 
instance is given. Since the seed itself can tell us little of its track, 
the necessity is urged of looking elsewhere for evidence of the modes 
of the working of the currents in transporting drift, and the writer 
accordingly appeals to the evidence supplied by bottle-drift, a subject 
to which the following chapter is devoted (pp. 39, 40). 

7. The chapter concludes with remarks on the transport of logs 
of mahogany to the coasts of Greenland, Iceland, and North-west 
Europe, and on the stranding of living turtles on the shores of the 
Hebrides, the Orkneys, and the Shetlands (pp. 40, 41). 

BIBLIOGRAPHY 

Batjhin, C, Pinax Theatri Botanici, 1623. (He quotes on p. 405 the work of 
Clusius (see below) as regards a drift seed since identified as belonging to 
Ipomcea tuberosa.) 

Baxjhin, J., Historia Plantarum, 1650. (Quoted by Sir D. Morris in connection 

with the drift fruits of Sacoglottis amazonica in Nature, January 31, 1889.) 
Borgesen. See under Warming. 



WEST INDIAN DRIFT ON EUROPEAN SHORES 43 



Brand, J., A Brief Description of Orkney, Zetland, Pightland-Firth and Caithness : 
Edinburgh, 1701. (Included also in Pinkerton's Voyages and Travels, 1809, 
iii., 789. Reprinted at Edinburgh in 1883.) 

Brooke, A. de Capell, Travels through Sweden, Norway and Finmark to the North 
Cape in 1820 : London, 1823. 

Claussen, P., A Description of Norway, 1632. 

Cltjsitjs, C. (De l'Escluse), Exoticorum Libri Decern, 1605. (See Note 2 at the end 
of this list. ) 

Debes, it. J., Fseroae og Fseroeske Indbyggeris Beskrivelse : Copenhagen, 1673. 
(Another title " Fseroa Reserata " is employed in the pages of Vibe and Fogh. 
An English translation by J. S. (John Sterpin) was issued in London in 1676.) 

Esslev, Tropical Drift on the Coast of Jutland, Det Danske Geografiske ; Selskab's 
Tidskrift, Nos. 3 and 4, p. 79, 1877; and Petermann's Mittheilungen, xxiii., 
316, 1877. 

Fielden, H. W., quoted by Hemsley in Annals of Botany, vi., 1892, concerning a 

drift seed of Ipomcea tuberosa in the Hebrides. 
Fogh, C, Golfstrommen, Tidskrift f. popular e Fremstillinger af Naturvidenskaben, 

Copenhagen, 1857, vol. iv., ser. i. [Quoted at length by Vibe (see below).] 

Gtjmprecht, T. E., Die Treibproducte der Stromungen im Nordatlantischen Ocean, 
Zeitschrift fur Allgemeine Erdkundt, No. 18, December 1854. 

Ounnertjs, J. C, on Scandinavian drift in Det Trondhjemske Selbskabs Skrifter, 
vol. iii. : Copenhagen, 1765. 

Hemsley, W. B., Reports of the " Challenger " Expedition, Botany, vol. i., part iv., 
1885. 

, Annals of Botany, vol. vi., 1892. 

Hepworth, W. W. Campbell, The Gulf Stream, Geographical Journal, November 
and December 1914. 

Humboldt, F. H. A. von, Voyage aux regions e'quinoxiales, vol. i. : Paris, 1807, etc. 

Irminger, C, on Iceland drift, Zeitschrift fur Allgemeine Erdkunde, 1854, iii., 187. 

Jonston, J., Historia naturalis de Arboribus et Fructibus, 1662. (Quoted by Sir 
D. Morris in Nature, November 21, 1895.) 

Kohl, J. G., Geschichte des Golf stroma und seiner Erforschung : Bremen, 1868. 

Latjghton, J. K., Physical Geography, 1873. 

Lindman, C, Om drifved och andra af hafsstrommar uppkastade naturforemal vid 
Norges kuster : Goteborg, 1883. [Quoted at length by Sernander (see below).] 

Lyngbye, H. C, Tentamen Hydrophytologiae Danicae, 1819. (In connection with 
the Faroe Islands.) 

Martin, M., A Description of the Western Islands of Scotland : London, 1703. 
(Martin Martin was a native of the Hebrides and took his M.A. degree at Edin- 
burgh in 1681. A second edition of his book was issued in London in 1716, 
and a reprint of the first edition in Edinburgh in 1884. In a copy of the 1716 
edition in the library of the British Museum there are marginal notes by 
J. Toland and Lord Molesworth, written about 1720-21. Toland flourished 
1670-1722. Martin's work is also included in Pinkerton's Voyages and Travels, 
1809, iii., 572.) 

Monaco, Prince of. The results of his experiments with floats in the North Atlantic 
were published from time to time in the Comptes Rendus de V Academic des 
Sciences between 1885 and 1892. Most of them were summed up in vol. cviii. 
(1889) ; but he subsequently recovered some more floats, and this led to a further 
summary with tabulation of results in vol. cxir. (1892). 

Morris, Sir D., on the drift fruits of Sacoglottis amazonica, etc., in Nature, January 
31, 1889, and November 21, 1895. 

Muller, K., Les Merveilles du Monde Vegetal. [Not consulted. The work is quoted 
in the English edition of Pouchet's UUnivers (see below).] 



44 PLANTS, SEEDS, AND CURRENTS 



Neill, P., A Tour through some of the Islands of Orkney and Shetland : Edinburgh, 
1806. [His references to Molucca Beans (pp. 60, 213) contain nothing that is 
not given by the Wallaces and others.] 

Ostenfeld. See Warming. 

Peel, C. V., Wild Sport in the Outer Hebrides, 1901. (There is a reference on p. 3 

to West Indian drift seeds.) 
Pennant, T., A Tour in Scotland and a Voyage to the Hebrides in 1772 : London, 

1790. (Also included in Pinkerton's Voyages and Travels, 1809, iii., 289.) 
Pettver, J., Musei Petiveriani : London, 1695 (octavo). 
, Gazophyllacii Naturae : London, 1702 (octavo). 

, Jacobi Petiveri Opera, Historiam Naturalem Spectantia aut Gazophylaceum : 

London, 1764. A large folio work in two volumes containing 1000 figures 
of natural history. The contents of all the plates are described with the 
exception of the first fiftv, the descriptions of which are given in the volume 
of 1702. 

Pontoppidan, E., Det forste Forsog paa Norges Naturlige Historie : Copenhagen, 
1751. [An English translation was published in London in 1755.] 

Potjchet, F. A., The Universe, translated from the French by J. R. Ainsworth Davis, 
1906, p. 394. Dr. Karl Muller in Les Merveilles du Monde Vegetal is quoted. 

Robert, E., Voyage en Islande et au Groenland, sous la direction de M. Paul Gei- 
mard, Mineralogie et Geologie, part i., p. 131 : Paris, 1840. (Reference is here 
made to the occurrence of seeds of Entada scandens at the North Cape and on 
the shores of the White Sea. In this connection Gumprecht (p. 421) quotes 
Robert in citing Le Bulletin de la Societt Geologique de France, xiii., 30.) 

Satjsstjre, Necker de, Voyage en Ecosse et aux lies Hebrides, iii., 22 : Paris, 1821. 
(With reference to the tropical drift of the Hebrides, Gumprecht (p. 416) quotes 
a paper of this naturalist in the Bibliotheque Britannique, Sciences et Arts, 1809, 
xlii., 90.) 

Schjoth, A., Om enkelte af Ha vets Phanomene (On different Marine Phenomena) : 
Christiania, 1848. Quoted by Vibe (see below). 

Sernandek, R., Den Skandinaviska vegetationens spridningsbiologi (The distri- 
bution-biology of the Scandinavian plant-world), mit einem deutschen Resume : 
Upsala, 1901. (An extensive bibliography is appended.) 

Sibbald, Sir R., Scotia Illustrata sive Prodromus Historiae Naturalis Scotise : Edin- 
burgh, 1694. (The earliest work known to the writer in which West Indian 
seeds stranded on the shores of Scotland and of the neighbouring groups of 
islands are designated "Molucca Beans.") 

Sloane, Sir Hans, Catalogus Plantarum qua? in insula Jamaica sponte proveniunt, 
1696, p. 214, quoted by Sir D. Morris in Nature, November 21, 1895, and by 
Gumprecht (p. 411). 

, An Account of four sorts of strange Beans frequently cast on shore on the 

Orkney Isles, Philos. Trans., xix., 298, 1695-7. 
, A Voyage to the Islands of Madera, Barbados, Jamaica, etc., 1707 and 1725. 

(Nearly all the work is occupied with " The Natural History of Jamaica," an 

island where he sojourned about fifteen months, 1688-9.) 
Strom, Physisk og Oeconomisk Beskrivelse over Fogderiet Sondmor beliggende i 

Bergens Stift f Norge : Soroe, 1766. (Quoted by Gumprecht on p. 420.) 

Tabern2EMONTANTjs. See Note 2 at the end of this list. 

Tonning, Amoenitates Academicce, vii., 477. (A pupil of Linnseus and the first botanist 
who identified the tropical fruits and seeds cast up on Scandinavian beaches.) 

Vibe, A., Kiisten und Meer Norwegens, in Petermann's Mitiheilungen, Ereangzungs- 
band, i., 1859-61. 

Waelenberg, G., Flora Lapponica, p. 506 : Berlin. 1812. 

Wallace, Rev. J., A Description of the Isles of Orkney by Master James Wallace, 
late Minister of Kirkwall, published after his Death by his Son : Edinburgh, 
1693. 



WEST INDIAN DRIFT ON EUROPEAN SHORES 45 



Wallace, Dr. J., An Account of the Islands of Orkney by James Wallace, M.D., 
F.R.S. : LoDdon, 1700. (This writer is the son of the Rev. J. Wallace. The 
work is his father's with additions, but without acknowledgment. In 1883 
there was published at Edinburgh a reprint of the 1693 edition, edited by J. Small, 
which included the materials added by the son in that of 1700.) 

Waltershattsen, Sartoritjs von, Physisch-geographische Skizze von Island, 1847. 

Warming, E., and colleagues, Botany of the Faeroe3 : Copenhagen, 1901-8. 

Worm, O., a Danish naturalist of the seventeenth century whose "Epistolfe" are 
quoted by Gumprecht (p. 420) in connection with Scandinavian tropical seed- 
drift. 

Note 1. — Gumprecht (pp. 421, 428-30) gives references in connection with drift- 
wood stranded in high latitudes in the North Atlantic to Petherick, Olafsen, Povel- 
sen, Crantz, von Lowenorn, de Pauw, Rennell, Irminger, Robert, Barrow, etc. 

Note 2. — Though the " Exoticorum Libri " of Clusius are mentioned by old and 
modern botanists in association with West Indian drift seeds, he merely described 
and figured certain unknown fruits and seeds that had been given to him and sup- 
plies no information about them. However, Gumprecht (p. 418) states that they 
were also described and figured " in seinen Anmerkungen zu des spanischen Botanikers 
Nicolas Monarde Bericht (Exotica, c. 49, p. 335) uber die Pflanzen Westindiens." 
He says the same (ibid.) of a botanical work of Tabernsemontanus, but gives no 
reference. 

Note 3. — Whilst this work was going through the press I have been able, through 
the kindness of Miss U. Warren, to inspect two seeds, evidently sound, of Entada 
scandens, which were found near Padstow on the north coast of Cornwall. 



CHAPTER III 



THE CURRENTS OF THE ATLANTIC AND THE TRACKS OF DRIFTING 
SEEDS AS ILLUSTRATED BY BOTTLE-DRIFT 

As indicative of the path followed by the drifting seed in its 
passage across the Atlantic and of the time occupied in the ocean 
traverse, the track of the drifting bottle offers very valuable data. 
But it may be at once stated that there is no intention of dealing 
here with all the materials which have accumulated in recent years 
with reference to this subject. They are merely sampled in these 
pages with the special object of throwing light on the interchange 
of seed-drift between the Old and the New World. Notwithstanding 
these limitations, the materials are quite as much as I can handle; 
and any extension of the inquiry would result in the opening up of 
the whole subject of bottle-drift, which would lead me far beyond 
the limits set for this discussion. 

One of the earliest to make a collection of bottle-drift data was 
H. Berghaus, who, in 1837, in the first volume of his Allgemeinen 
Lander und Volkerkunde, published a list of twenty-one bottle-drifts, 
and laid down in a chart in his Physikalischen Atlas several interest- 
ing examples. I have not had access to these works, and am 
indebted to Schott for the reference. Shortly afterwards a chart of 
bottle-drifts constructed by Daussy, a Frenchman, is stated to have 
been published; but I have not been able to find it. It is men- 
tioned by Kohl in his Geschichte des Golfstromes (1868); but the 
author's name is given as Dayssy, and one is referred for particulars 
to Nouvelles Annales des Voyages (tome lxxxii., Paris, 1839), where 
one finds only a brief notice of the results obtained. Schott (p. 2) 
alludes to the missing chart, but he merely quotes Kohl. After 
some search I found in Comptes Rendus (tome viii., p. 81, 1839) a 
short paper of two and a half pages by M. Daussy, entitled " Sur les 
observations de courants faites au moyen de bouteilles jetees a la 
mer." He states that he had utilised ninety-seven bottle-drift 
observations in his table and chart, which, however, do not accom- 
pany his paper. Probably they lie among the unpublished records 
of the Academie des Sciences of Paris. 

Major Rennell, in his Investigation of the Currents of the Atlantic 
Ocean (1832), deals with the subject, and especially with the bottle- 
drift from high northern latitudes, many interesting examples being 
given. In 1852 Commander Becher published in the Nautical 
Magazine, with charts, the data for about 180 bottle-drifts in the 
North Atlantic, two-thirds of which had been previously published 

46 



I 

1 
I 



CURRENTS OF THE ATLANTIC 47 



in the same journal for 1843. These results, where suitable, have 
been utilised by me. However, most of my materials have been 
supplied from the results gathered in recent years by the United 
States Hydrographic Office in Washington and by the Deutsche 
Seewarte in Hamburg. The first were published on the backs of 
the North Atlantic Pilot Charts, while the second were embodied in 
Dr. Schott's memoir Die Flaschenposten der Dzutschen Seewarte , 
1897. By far the most extensive and systematic inquiry ever made 
in this direction was that conducted by Albert, Prince of Monaco, 
from 1885 to 1887. Floats, specially devised, were employed; but 
the mode of presentment of his results and the absence of his chart 
have stood in the way of my employing them as much as I could 
have wished. As will be seen from the following pages, however, 
they have proved of great value. 

Whilst my facts for the North Atlantic are mainly derived from 
the American Pilot Charts and for the South Atlantic from Dr. 
Schott's work, those for the equatorial seas are chiefly derived from 
both these sources and to a less degree from the Nautical Magazine. 
With great courtesy the U.S. Hydrographic Office supplied me 
with a set of four bottle-drift charts, covering the eight months 
from October to May 1900-8, and affording the data and tracks 
for about 650 bottles. Dr. Schott, whilst preparing his memoir, 
had at his disposal the materials for 643 bottle-drifts in the Atlantic, 
Indian, and Pacific Oceans. Of these 452 are concerned with the 
North Atlantic and 102 with the South Atlantic, forty-three with 
the Indian Ocean, and forty-six with the Pacific Ocean. The tracks 
for most of the Atlantic bottle-drifts are laid down in his charts. 
Thus in the case of the North Atlantic about three-fourths are thus 
laid down. The tracks of all those in the Indian and Pacific Oceans 
are represented in separate charts, and some highly interesting data 
are given for a few bottles in the belt of the Westerly Winds in high 
southern latitudes. But the weak point in the memoir is the deficient 
supply of facts relating to the duration of each drift. In this respect 
Dr. Schott only samples the subject, referring the reader for the 
complete data to the Archiv der Seewarte and the Annalen der Hydro- 
graphie. However, sufficient materials are given in his pages for the 
elucidation of this part of the inquiry. 

With regard to the Prince of Monaco's investigations during three 
voyages in the North Atlantic, 1885-7, it may be said that in the 
first voyage (1885) 169 floats were dropped into the sea to the north- 
west of Corvo in the Azores. In the second (1886) as many as 510 
floats were cast over about midway between the Azores and South- 
western Europe along a line, 450 miles in length, nearly on the 
meridian 17° 40' W. of Greenwich and between the latitudes of 
42° 32' and 50° N. In the third voyage 931 floats were thrown over 
between the Azores and the Banks of Newfoundland and sixty-five 
to the north of those islands, at average intervals in most cases of 
1180 metres, along a line 700 miles in length. Out of this total of 
1675 floats, 226, or 13^ per cent., were recovered. From time to 
time, between 1885 and 1892, the results were given to the world in 
the Comptes Rendus hebdomadaires des Sciences. Most of them were 



48 PLANTS, SEEDS, AND CURRENTS 



summed up in Vol. CVIII. (1889) ; but fifty-six floats were afterwards 
returned, and this led to a final summary and tabulation of results 
in Vol. CXIV. (1892). This final report is said to have been accom- 
panied by a chart in which the Prince of Monaco laid down the 
tracks of all of the recovered floats. This chart, to my great dis- 
appointment, I failed to find. Reference to these very important 
investigations has been made in various English journals, such as 
Nature and the publications of the Royal Geographical Society. 
The Prince himself contributed a general account of his results to 
the Proceedings of the Society just named for 1892 in a paper 
entitled " A New Chart of the Currents of the North Atlantic." 
He read a paper before the British Association in 1892, but it is not 
given in the Annual Report. His results will be utilised, as occasion 
requires, in the succeeding pages ; but it may be here observed that 
these floats were stranded on all the eastern shores of the North 
Atlantic from the North Cape to Morocco. About 9 per cent, of the 
recoveries were returned from the Canary Islands and about 10 J per 
cent, from the West Indies and Central America. The reader will 
perhaps be surprised at the large number of these floats that reached 
the tropical regions of the New World, and this will prepare him for 
much that follows in the succeeding pages of this chapter. 

The Value of Bottle-drift Data for the Study of the 
Dispersal of Seeds by Currents. — I will not enter here into the 
old controversy as to the value of bottle-drifts for the investigation 
of currents. Here, as in most other controversial matters, the via 
media between wholesale condemnation and uncritical acceptation 
may be confidently pursued. We are only now concerned with the 
surface-flow, which is all that the currents signify for us in the 
transport of floating materials. Although, as the compiler of the 
American charts remarks, the individual drifts are but the resultant 
effect of all the forces to which the bottle is exposed during its 
passage, yet, as he goes on to say, the tracks followed by these float- 
ing bottles furnish a fair conception of the drift- currents. When 
we look at the American and German charts and notice how uniform 
and consistent is the direction taken by bottles cast into the sea 
within the limits of well-known currents like the Gulf Stream and the 
Main Equatorial Current, it would be idle to cavil at the assumption 
that they are transported by these currents. The water-logged 
derelict from off Cape Hatteras, the baulk of mahogany from West 
Indian waters, the living turtle from the warm latitudes of the New 
World, the floating bottle containing the record of its start in Cuban 
waters or in Florida seas, the buoyant seed that could only have 
grown in the West Indian islands or on the tropical mainland of 
America, all tell the same story when they reach the coasts of 
Europe. 

The Proportion of Recoveries. — Naturally, the proportion of 
recoveries among ordinary bottles is small; but much depends on 
locality. Dr. Schott especially alludes to this matter (p. 3, etc.). 
The proportion may be as high as 10 per cent, in the case of bottles 
dropped overboard in the warm latitudes of the middle of the 
Atlantic, whence they are borne westward to the West Indies; and 



CURRENTS OF THE ATLANTIC 49 



when conspicuous, specially devised floats are used, as with the 
Prince of Monaco's investigations in the North Atlantic, it may be 
as much as 13J per cent. Very few bottles are returned from the 
West African coasts, and the same may be said of those thrown 
over in high southern latitudes. In the last case the rare recoveries 
possess a high interest. Thus out of sixty bottles dropped over- 
board by Dr. G. Neumayer during a voyage in 1864 from Australia 
to the equatorial Atlantic by Cape Horn, only one was recovered 
after a lapse of four years, and that was a bottle that was drifted 
from Cape Horn to South-east Australia (Schott, p. 2). A similar 
experience is recorded in the London Times for April 17, 1912. Of 
forty bottles dropped overboard during a voyage in 1908 from 
London to Melbourne by the Cape of Good Hope, only one record 
was returned, and that was concerned with a bottle which was 
washed up on the coast of Chile, after drifting from a position 
lying some hundreds of miles to the south-west of Cape Leeuwin, 
Australia. 

The Difficulties connected with the Delay in the Recovery 
of the Bottles. — These difficulties prove to be not so great as at 
first they seem to be. The belated " finds " become very evident 
when one handles numerous data for the same drift-passage ; and at 
times the records for a set of bottles dropped over at or near the 
same time display internal evidence of critical value. Thus, if the 
one that has travelled the longest distance is found first, it is fair to 
infer, in the case of transatlantic drifts, that the delay in its recovery 
was relatively short. As explained in a later page, in order to 
eliminate this disturbing element as much as possible, I have utilised, 
when estimating the average drifting-rate for a particular traverse, 
only the records for the bottles with the quickest rates up to 20 or 25 
per cent, of the total. I have since ascertained that the Prince of 
Monaco adopted a similar method in determining the mean velocity 
of the " drifts." When they were numerous, he took the average of 
the fastest third or fourth. When they were few, he selected the 
most rapid example. At times the remark of the finder that the 
bottle appeared to have been stranded at the last tide is very service- 
able; but the record is particularly valuable when, as occasionally 
happens, the bottle has been found afloat. 

The Tracks of Bottles thrown Overboard together. — 
Interesting results are supplied by the American charts in the cases 
of bottles thrown over together off the eastern coasts of the United 
States. They may be distributed fanwise, and are then cast ashore 
on the coasts of Europe in places far removed from each other, or 
they may be recovered on the European side only a few miles apart. 
Thus, out of eight bottles thrown together into the sea off Cape 
Hatteras from the s.s. New York on March 24, 1906, one was found 
on the coast of Scotland, two on the Irish coast, two near Arcachon 
on the shores of the Bay of Biscay, one in the Azores, one in the 
Bermudas, and one on Grand Turk at the southern end of the 
Bahamas. As an example of bottles drifting in company across 
the Atlantic, I will take the case specially noted in these charts. 
From the s.s. Cherokee two bottles were put overboard together near 

E 



50 PLANTS, SEEDS, AND CURRENTS 



Cape Hatter as on October 26, 1905, and they were recovered on 
June 10 and 19, 1907, in the vicinity of Bray Head and Cape Clear 
on the south-west shores of Ireland, about fifty miles apart as the 
bird flies. A very remarkable instance of this kind is recorded by 
Mr. Wood-Jones in the Indian Ocean, though there was here an 
unexplained delay in the recovery of one of the bottles. Two bottles, 
dispatched on November 15, 1905, from Keeling Atoll, were found 
at " exactly the same spot " at Brava on the coast of equatorial 
East Africa in 1° 6' N. lat. The first was recovered on May 27, 
1906, and the second on July 11, 1907 (Coral and Atolls, pp. 294-5, 
1910). It is probable that these two bottles drifted together and 
that from some cause the second was overlooked. 

But this is the exception and not the rule. Rennell, in his book 
on the Atlantic currents, refers to two bottles thrown over from 
H.M.S. Newcastle on June 20, 1819, rather over 300 miles south-east 
of Cape Cod in localities about twenty miles apart, one of which was 
picked up on May 20, 1820, on the north coast of San Jorge in the 
Azores, and the other near the island of Aran on the north-west coast 
of Ireland on June 2, 1820, the difference in latitude represented by 
the divergence of the two tracks being about sixteen degrees. [These 
two cases are included by Becher in his list of bottle-drifts in the 
Nautical Magazine for 1852 (Nos. 97 and 98), but the positions there 
given of the starting-places are about sixty miles apart.] The 
separation of bottles thrown over together may be soon effected, 
even where there is no reason to suspect the presence of contiguous 
currents. Schott (p. 18) alludes in this connection to Hensen's 
experiment in Kiel Bay with ten weighted glass globes, which after 
twenty-four hours displayed an extreme separation of a German 
mile (nearly five English miles). Of course, when the bottles are 
dropped overboard in the disputed area between two contrary cur- 
rents, as in the case of the Main Equatorial Stream and the Guinea 
Current, great divergencies are to be looked for. A striking instance 
is mentioned in Note 19 of the Appendix. Of two bottles that were 
cast over together in the vicinity of St. Paul's Rocks in the middle 
of the Atlantic, one was thrown ashore on the coast of Sierra Leone 
and the other on the shores of Nicaragua. 

The Divergent Tracks of Derelicts and Casks. — Derelicts 
display some curiously divergent courses in the North Atlantic. 
Reference is made in Notes 15 and 16 of the Appendix to two dere- 
licts which commenced their drifting passage within sixty miles of 
each other, about 200 or 250 miles north of Cape Hatteras, at the 
same season (February and March), but in different years. One was 
stranded in the Hebrides and the other on the Panama Isthmus, 
after periods of ten and eighteen months respectively. Water- 
logged derelicts are especially instructive, since their position at 
different stages of their track is often determined by the observations 
of passing vessels. In the Nautical Magazine for 1843 (p. 757) and 
1852 (p. 672) allusion is made to the drift of some casks of blubber 
from the ship William Torr that was wrecked in Davis Straits. As 
they were carried eastward and southward towards Ireland and the 
north of France they became more and more separated, so that 



CURRENTS OF THE ATLANTIC 51 



after crossing the 20th meridian of west longitude, a drift probably 
of at least 1500 miles, the most northerly and southerly casks were 
nine or ten degrees of latitude apart. 

The Circulatory Movement of the Surface-waters of the 
North Atlantic. — Broadly viewed, to adopt the standpoint of the 
Prince of Monaco, this movement has its centre somewhat to the 
south-west of the Azores. The circumferential waters, after skirting 
the eastern shores of North America, cross the ocean to the shores of 
Europe, and then bending south along the African coast, curve west 
in the vicinity of the Cape Verde Islands and follow the line of the 
North Equatorial Current to the West Indian region. Between the 
tracks involved in a very long circuit at the circumference of the 
movement and a very short one around its centre several inter- 
mediate tracks are possible for drift. 

With these preliminary remarks I will at once proceed to deal with 
the evidence of the drifting bottle, and it may be here said that it is 
with the long outer circuit of the North Atlantic that the tracks of 
the bottles laid down in the American and German charts are mainly 
concerned. They represent the course followed by West Indian 
drift in reaching Europe, and the course that would be afterwards 
pursued by the same drift in returning to the West Indian region, 
or by European and West African drift in reaching the New World. 
A large segment of this circuit did not come within the area covered 
by the Prince of Monaco's investigations, namely, that lying between 
the West Indies and a line uniting Newfoundland with the Azores. 
It is here that the materials supplied by the American charts are 
most valuable. 

Whether the circuit is accomplished by the same bottle or by 
different bottles the indications are the same. Even if it cannot 
often be absolutely demonstrated by one example (see Note 15 of the 
Appendix), the circuit of the North Atlantic can be illustrated in 
piecemeal fashion by the records of two or three examples. Leaving 
the warm waters of the West Indian seas, the drifting bottle would 
be carried swiftly by the Gulf Stream through the Straits of Florida, 
whence it would be borne northward past Cape Hatteras to the 
parallels of 40° to 45° south of Cape Race. Then, coursing eastward, 
it would, on approaching the 40th meridian of west longitude, come 
to a parting of the tracks. Whilst the great bulk of the drift would 
continue its easterly course towards the shores of Europe, a portion 
would be deflected south to the Azores. Much of this would be 
stranded on these islands, but much also would traverse the group, 
and after passing well to the westward of the Canaries would come 
within the influence of the North Equatorial Current, ultimately 
reaching the Bahamas or the Florida coasts, or even the Bermudas. 
But our interest lies with the fate of the great mass of the drift. 
Continuing its easterly course, but with a northerly trend, most of 
it would be spread out fanwise and would be distributed over the 
whole length of the western shores of Europe from the North Cape 
to Cape St. Vincent, even reaching Morocco. Yet a small portion of 
it would keep to the open ocean. Carried south in the Portuguese 
Current, it would leave samples of its materials on the beaches of 



52 PLANTS, SEEDS, AND CURRENTS 



Madeira and the Canary Islands, and after approaching the vicinity 
of the Cape Verde Group it would get into the full stream of the 
North Equatorial Current, and thus be borne to the West Indian 
region. Whilst, as already indicated, the conclusions for the first 
portion of this circuit are mainly based on the American charts, 
those for the remainder are also founded on the Prince of Monaco's 
results. With these introductory remarks I will first deal with the 
traverse of the North Atlantic by drift from the American to the 
European side of the ocean, and afterwards with the return passage 
from European and African waters to the West Indian region. 

The Passage of Bottle-drift from the West Indies and the East Coasts 
of North America to the Shores of Europe 

TABLE I 

The traverse from the West Indies to the shores of Europe 

(Compiled from the American, German, and English sources above named. The 
columns A, B, C, D, indicate not only the starting-places of the bottles, but also 
the track pursued by them in the passage from the New to the Old World. The 
circuit of the North Atlantic is also illustrated by those bottles, which, on approach- 
ing the shores of Europe, were deflected south, and after passing through the Canary 
Islands, were returned to the West Indian region in the North Equatorial Current.) 





Locality where thrown Overboard 








A 


B 


C 


D 






Place of Recovery 


Eegion 
between 
Florida, 
Cuba, and 
the Bahamas 
(21°-27° 
X. lat.) 


Vicinity of 

Cape 
Hatteras 
(34°-36° 
ST. lat.) 


Region 
south of 
Sable Island 
and Cape 

Race 
(40°-45° 
N. lat.) 


Region in 
mid-Atlantic 
lying N.W. 
of the 
Azores 
between 
30° and 40° 
W. long, and 
45° and 50° 
& lat. 


Total 


Per- 
centage 


Iceland . 
Norway . 
Sweden . 
Shetland Islands 
Orkney Islands . 
Scotland and the 

Hebrides . 
Ireland . 
England . 
France . 
Portugal . 
Azores 
Morocco . 
Madeira . 
Canary Islands . 
West Indies . 
Bermuda 


1 

1 

3 
2 
2 

1 


T 
i 
i 
i 

6 
7 
1 
8 

9 
1 

2 


1 
1 

3 
10 
4 

2 
2 
8 
2 

2 

1 


1 

3 

2 
5 

8 

2 

1 

1 


2 
5 
1 
1 
2 

12 

25 
7 

20 
2 

20 
3 
1 
2 
3 
1 


2 

4-5 

1 

1 

2 

11 

23 

6-5 
18-5 

2 

18-5 
3 
1 
2 
3 
1 




10 


38 


36 


23 


107 


100-0 



CURRENTS OF THE ATLANTIC 53 



The Passage op Bottle-drift from the West Indies and the East Coasts 
of North America to the Shores of Europe (continued) 

TABLE II 

The results of the researches of the Prince of Monaco 

(The specially devised floats employed were deeply immersed and were thus less 
likely to be directly influenced by the wind than the ordinary bottle as usually em- 
ployed. Only the latter part of the traverse from the West Indian region to the 
shores of Europe is here illustrated, namely, the portion east and north of a line 
drawn from the Azores to the Banks of Newfoundland. Quite two-thirds of the 
floats were dropped into the southern half of the area traversed by the Gulf Stream, 
using that term in a general sense; and this explains the large percentage of floats 
that were deflected south to the Canaries and ultimately reached the West Indies 
in the North Equatorial Current.) 





Locality 


where thrown Overboard 








A 




C 








(1885) 


(1887) 


(1886) 








North-west of 










Place of Recovery 


the Azores. 
(Along a line 
stretching 
from 117 to 


Between the 
Banks of New- 
foundland and 


North-east of 
the Azores. 
(Between 
42° 30' and 


Total 


Per- 
centage 




270 miles 


the Azores. 










N.N.W. of 
Corvo, lat. 
41°-44° N., 
and long. 


(Along a line 
joining these 
two localities. 1 ) 


50° N. lat. 
and along the 
meridian 
17° 30' W.) 








32°-33° W.) 










Iceland .... 




3 




3 


1-3 


Norway .... 




22 




22 


10 


Denmark .... 




1 




1 


0-5 


Scotland, Hebrides, 












Orkneys, Shetlands 




9 




9 


4 


Ireland .... 




18 




18 


8 


England . ■ . 




2 




2 


1 


France .... 




12 


24 


36 


16 


Spain and Portugal . 


1 


12 


18 


31 


14 


Azores .... 


11 


26 




37 


16-5 


Tunis 






1 


1 


0-5 


Morocco .... 




1 


6 


7 


3 


Madeira .... 


1 


5 




6 


2-7 


Canaries .... 


1 


14 


6 


21 


9-5 


West Indies . 


4 


13 


6 


23 


10-5 


Yucatan .... 




1 




1 


0-5 


Bermuda .... 




3 


1 


4 


2 




18 


142 


62 


222 


100-0 



The Passage of Bottle-drift from the West Indies and the 
East Coasts of North America to the Shores of Europe. — This 
traverse is well illustrated in the two tables above, about which a 
few explanatory observations may here be made. Three-fourths of 
the materials employed in the first table are furnished by the Pilot 

1 The Prince of Monaco includes in these results a small group of floats (about an 
eighth of the total) dropped overboard due north of the Azores between the positions 
49° 31' N. and 29° 7' W. and 48° 58' N. and 26-7 W. 



54 PLANTS, SEEDS, AND CURRENTS 



Charts of the North Atlantic published by the United States Hydro- 
graphic Office for the eight months October to May 1900-8, the 
rest being supplied by Dr. Schott's memoir Die Flaschenposten der 
Deutschen Seewarte (1897), the Nautical Magazine for 1852, and in a 
few cases from sundry sources. The second table deals with the 
results of the researches of the Prince of Monaco, and have been pre- 
pared from his papers in the volumes of the Comptes Rendus from 
1885 to 1892. 

In the first table there are given the records for 107 bottles that 
started from the four regions A, B, C, D in their traverse of the 
North Atlantic. Since all the four starting-places lie in the main 
track of the drifting bottles from the tropics of the New World to 
the shores of Europe, the limits being determined by the data them- 
selves, it follows that all the materials in this table may be used to 
illustrate the passage of West Indian bottle-drift to the shores of 
Europe. But this table tells us more. It tells us of the bottles that 
were deflected south when approaching European waters, and were 
ultimately returned to the West Indian region in the North Equatorial 
Current. In other words, it also illustrates the completion of the 
circuit of the North Atlantic. With this last, however, we are not 
here specially concerned, except in so far as it informs us of the 
distribution of bottle-drift that leaves West Indian waters on its 
transatlantic passage. 

The course pursued is determined by the Gulf Stream. After 
emerging from the Florida Strait, the bottles are borne northward 
by this current past Cape Hatteras towards Nova Scotia and New- 
foundland, and then eastward with a northerly trend towards Europe, 
spreading out in a fan-like fashion after crossing the 40th meridian 
of west longitude to the north-west of the Azores. About 18 per 
cent, of the bottles dealt with in the table were soon diverted south 
and stranded on the Azores, but by far the greater number, amount- 
ing to about 75 per cent., were distributed over all the exposed 
coasts from the North Cape of Norway to Morocco. The remaining 
seven of the hundred bottles, still speaking of them in a proportional 
sense, were borne in the Portuguese or North African Current yet 
further south. One was beached on Madeira, two on the Canary 
Islands, and four came within the influence of the North Equatorial 
Current and were ultimately recovered in the Lesser Antilles, the 
Bahamas, and the Bermudas. Of those just mentioned as reaching 
the West Indian region, one from the middle of the North Atlantic 
was picked up in the Turks Islands at the south-east end of the 
Bahamas, whilst two from off Cape Hatteras were found respectively 
on the island of Anguilla in the Lesser Antilles and on that of Eleu- 
thera in the North- west Bahamas, the circuit of the North Atlantic 
being almost completed in the last case. 

It may here be observed that the fan-like distribution of bottle- 
drift from the New World on the coasts of Europe, though naturally 
most pronounced when we lay down on a chart the tracks of numbers 
of bottles from the same locality covering a period of several years, 
is also well exhibited in the case of bottles thrown over together. 
This is well exemplified in the case of bottles that begin the ocean 



CURRENTS OF THE ATLANTIC 55 



traverse in the vicinity of Cape Hatter as. If we take a period of 
years, they may be distributed, as shown in the preceding table, 
over the whole stretch of seaboard from the north of Norway to 
Morocco, which represents a range of about forty degrees of latitude. 
These bottles were dropped over not only in different years, but in 
different seasons and within an area covered by two degrees of 
latitude. One could scarcely expect such a divergence of tracks in 
the case of bottles thrown overboard together off the same headland. 
Yet it may be large ; and in this connection reference may again be 
made to the divergence of the eight bottles thrown over together off 
Cape Hatteras (see p. 49). Of the five thrown up on the shores of 
Europe, the extreme range in latitude was almost eleven and a half 
degrees, the northernmost being cast up on the island of Colonsay off 
the west coast of Scotland and the southernmost on the shores of the 
Bay of Biscay in the vicinity of Arcachon. Yet we have to assume a 
much greater divergence for the whole group of bottles, since three of 
them were deflected south and were recovered on the Azores, the 
Bahamas, and the Bermudas. 

Various disturbing influences doubtless affect in different years 
and seasons the distribution of drift from the New World in its 
traverse of the North Atlantic. But of this we may be assured that 
there is no one tract of seaboard on the European side that receives 
all its transatlantic drift from the same region of the New World. 
The Irish coasts receive drift from all latitudes on the American side 
of the North Atlantic between the Caribbean Sea and Davis Strait. 
So also the North Cape of Norway receives drift alike from the 
Greenland coasts, from off Cape Hatteras, and from the Florida seas. 
For particulars relating to bottle-drift from Davis Strait and the 
south end of Greenland reference may be made to the concluding 
remarks of Note 27 of the Appendix. 

Coming to the Prince of Monaco's results in the second table, it 
may be at first observed that they only lend themselves in part for 
the discussion of the traverse of the North Atlantic from the New to 
the Old World, since they are not concerned with the first half of the 
passage from the Florida Straits to a line drawn from the Newfound- 
land Banks to the Western Azores, and even with this limitation 
their indications mainly apply to the southern portion of the drift 
that the Gulf Stream bears eastward towards Europe. But what 
we lose in one way we gain in another, since they offer a splendid 
illustration of the circulatory movement of the surface-currents of 
the North Atlantic, which formed one of the principal objects of this 
unrivalled series of investigations. It will be observed that the 
results for 1885 and 1886 mainly illustrate this southern divergence 
of the drift, which begins to the north-west of the Azores and is 
continued until after the 20th meridian of west longitude is crossed. 
Of the eighty floats recovered in these two sets of observations, not 
one was found north of the coasts of France, and ten of them, or a 
proportion of 12 J per cent., were returned to the Prince of Monaco 
from the West Indies. This is four times as great as that represented 
in Table I. for bottles that in reaching the West Indian region have 
practically performed the circuit of the North Atlantic; and it 



56 PLANTS, SEEDS, AND CURRENTS 



should be noticed that the proportion of bottles stranded on Madeira 
and the Canaries is tripled in the case of the Prince of Monaco's 
floats thrown over in 1885 and 1886. 

The Prince's results for 1887 are most suited for comparison with 
those of Table I. But even here it is obvious that if we make a 
cross-section of the Gulf Stream drift in mid-Atlantic, these results 
are more concerned with the southern half than with the northern 
half of the section. Thus the great increase in the proportion of 
floats deflected towards warm southern latitudes is here repeated, 
about 13 per cent, being carried to Madeira and the Canaries and 
about 10 per cent, to the West Indian region. This tendency is well 
exhibited in the differences in the two cases between the proportions 
of bottles or floats stranded on the European side of the Atlantic in 
latitudes north of the French coasts. This proportion in the case of 
the results given in Table L is as much as 51 per cent., whilst for the 
results obtained by the Prince of Monaco for 1887 it is barely 39 
per cent. 

With these exceptions, most of the principal features in the dis- 
tribution of transatlantic drift that are illustrated in Table I. are 
reproduced in the Prince of Monaco's results. His floats were found 
on all coasts of the European side of the North Atlantic from Norway 
to Morocco, and they even penetrated into the Mediterranean. It 
may be added that the large proportion of the floats recovered in 
Norway in the series of experiments made in 1887 is to some extent 
counterbalanced by the diminished proportion found on the coasts of 
Ireland and Scotland, inclusive of the islands near. 

The Passage of Bottle-drift from the European and African 
Side of the North Atlantic to the West Indies.— This has 
already been demonstrated by implication from the data in the 
previous tables that are employed to establish the completion of the 
circuit of the North Atlantic by drifting bottles and floats. But we 
will here deal with those bottles that commence the ocean traverse 
in European or African waters, or in different parts of the track to 
the New World; in other words, with those that perform the last 
half of the circuit. As before observed, bottle-drift in European 
waters is carried south in the Portuguese or North African Current 
past Madeira and Canary Islands to the vicinity of the Cape Verde 
Group, whence it is borne westward in the North Equatorial Current 
to the West Indies. Before discussing this subject I will give the 
materials on which my conclusions are based (see table, p. 57). 

Although the table largely explains itself, some additional remarks 
may here be made; and in the first place I will give a few details 
about the 44 places of recovery." Most of the bottles entered in 
Column A, under the heading 44 Bahamas," were recovered at the 
south-east end of the Bahamian group, namely, on the Turks, Caicos 
and adjacent islands. Out of the twenty-six there recorded, twenty 
are thus accounted for. Two were found in the middle of the group 
and four at the north-west extremity. Of the twenty bottles found 
in the Greater Antilles, as given in Column B, four were stranded on 
the south coast of Jamaica and on the small islands near, whilst all 
the rest were beached on the coasts of Cuba, Hispaniola and Porto 



CURRENTS OF THE ATLANTIC 57 



Table Illustrating the Passage of Bottle-Drift from the European 
and African Side of the North Atlantic to the West Indies 

There are here shown the places of recovery in the West Indies and on the 
American mainland of bottles thrown over in most cases on the eastern side of the 
North Atlantic between the south-west of Ireland and the Cape Verde Group and 
transported across the ocean in the North Equatorial Current. 

(The materials are derived from the bottle-drift charts of the U.S. Hydro- 
graphic Office for October to May 1900-8, from Dr. Schott's Die Flaschenposten der 
Deutschen Seewarte, 1897, from Commander Becher's papers in the Nautical Magazine 
for 1852, from Major Rennell's Investigation of the Currents of the Atlantic Ocean, 
1832, etc. ; the two first named being the principal sources.) 





Places of Recovery 








A 


B 


C 


D 


E 


F 






Starting place 


lamas 


eater 
itilles 


;sser 
itilles 


lduras 
iragua 


llf of 

exico 


orida 


Total 


Remarks 










o w .g 

w & 




5 






Off the S.-W. 
coast of Ireland 


1 












1 


From the 
land 260 miles 


Off the coasts 

of Sna.in fl.nrl TVir- 

tugal 


2 


2 


9 


1 






14 


Within the 
region 36°-45° 
N. lat., 9°-20° 
W. long. 


Vicinity of Ma- 
deira and the 
Canary Islands 


6 


6 


3 




2 




17 




About midway 
between the Can- 
ary and Cape 
Verde Islands 


3 


4 


3 


4 


1 


1 


16 




Vicinity of the 
Cape Verde Is- 
lands 


7 


4 


13 


5 




3 


32 


Within the 
region H°-19° 
N. lat., 21°- 
30° W. long. 


Mid-Atlantic, 
about half-way 
between Cape 
Verde and the 
West Indies 


7 


4 


12 


2 






25 


Between 13° 
and 21° N. lat. 
and 35° and 
50° W. long. 


Totals . . . 


26 


20 


40 


12 


3 


4 


105 




Percentages . 


25 


19 


38 


11 


3 


4 


100 





Note. — The percentages may be taken as illustrating the distribution of drift carried 
by the North Equatorial Current to the tropics of the New World from the European 
and African side of the Atlantic. 



58 PLANTS, SEEDS, AND CURRENTS 



Rico. In the cases of Cuba and Hispaniola they were found in about 
the same proportions and equally distributed on both the north and 
south sides of the islands. Those mentioned under Column C were 
well distributed over the Lesser Antilles north of Barbados and 
St. Vincent, and, with the exception of one stranded on the Grena- 
dines, never south of those two islands. Of the remainder it may 
be said that most of those brought to the shores of Honduras and 
Nicaragua were found in the former region, that those carried 
through the Straits of Yucatan into the Gulf of Mexico were either 
cast up on the coasts of Texas and Louisiana or were hurried along 
in the Gulf Stream and deposited on the east coast of Florida. 

Taking the bottles starting from the eastern side of the ocean, no 
consistent discrimination can be made between the groupings of the 
places of recovery and the starting localities. As far as the data go, 
they show that almost from every one of the localities bottles may 
be transported all over the West Indian islands north of Barbados 
and St. Vincent. South of these two islands is the track by which 
the drift of the Main Equatorial Current chiefly enters the West 
Indian region ; whilst on the north, extending as far as the Bahamas, 
lies the area that receives the drift of the North Equatorial Current. 
It is with the distribution in the West Indian region of the drift 
brought across the North Atlantic by this current from latitudes, 
generally speaking, north of the tenth parallel (N. lat.) that the 
table above given is exclusively concerned. The concentration of 
drift at the south-east end of the Bahamas is remarkable. One- 
fifth of all the bottles brought by the North Equatorial Current to 
the West Indian islands was stranded on the Turks, Caicos and 
neighbouring islands. 

The noticeable proportion of bottles stranded on the east coast of 
Florida, after being thrown over in the vicinity of the Canary and 
Cape Verde Islands, is a feature of the foregoing table. Those that 
have crossed the Caribbean Sea, after passing through the islands of 
the Lesser Antilles, often strike the coasts of Nicaragua and Hon- 
duras; but almost as many pass to the northward through the 
Straits of Yucatan, and, if not beached on the north-western shores 
of the Gulf of Mexico, enter the Florida Straits and are thrown up, 
as in the case of these bottles, on the east coast of Florida. The 
story of the bottle-drift cast up at different stages of the long passage 
from the African side of the North Atlantic to the Florida seas 
clearly indicates the track across the Caribbean Sea and the Gulf of 
Mexico ; and both the American and German authorities are at one 
on this point. At the same time it is evident that occasionally the 
Florida waters may be reached by the shorter route through the 
Bahamas by the agency of the Antillean Stream, a subject referred 
to later on in this chapter and in Note 13 of the Appendix. 

It is to be expected that bottles which reach the Florida seas, 
after drifting across the North Atlantic from the African side, would 
sometimes be caught in the rapid current of the Gulf Stream in the 
Florida Straits and be carried northward and eastward to the coasts 
of Europe. It is brought out in the previous tables (pp. 52, 53) 
that this is not infrequent with bottles dropped overboard in the 



CURRENTS OF THE ATLANTIC 59 



Florida region; and we have a good example in the case of those 
from the African side numbered 206 in Schott's memoir (map ii., 
pp. 9, 23, 26). Starting from a position about 150 miles south-west 
of the Cape Verde Islands (lat. 13° 16' N., long. 25° 51' W.) on May 19, 
1887, it was recovered at Clifden, on the west coast of Ireland (Co. 
Galway), on March 17, 1890. The distance traversed in its passage 
in the North Equatorial to the West Indies, and thence to Europe 
in the Gulf Stream drift, was computed at 7700 miles by the southern 
route through the Lesser Antilles and then across the Caribbean Sea 
and the Gulf of Mexico, and at 6300 miles by the more direct northern 
passage between the Bahamas and the Greater Antilles. Dr. Schott 
gives a facsimile of the paper enclosed in the bottle, duly filled up 
and signed by the sender and the finder. It is not possible to deter- 
mine which of the two routes in West Indian waters this bottle 
pursued; but that drift from the Caribbean Sea may reach the 
shores of Europe is indicated by the track of a bottle (No. 110) in 
the Nautical Magazine for 1852. It was thrown over about a hundred 
miles off the south coast of Jamaica in lat. 16° N. and long. 78° 5' W., 
and was found on the coast of Ireland ; but the time occupied in the 
drift is not supplied. Such are some of the principal indications 
afforded by bottle-drift of the work that would be performed by the 
North Equatorial Current in carrying seed-drift from the Old to the 
New World. 

However, some curious questions arise in connection with the 
debatable region of the Guinea Current. To the southward of the 
Cape Verde Group and confined between the parallels of 2° S. and 
10° N.j and between the meridians of 20° and 32° W., lies a region in 
which the bottles become the sport of conflicting currents. Here 
the Guinea Current flowing east is interposed between the North and 
Main Equatorial Currents flowing west, and, owing to the shifting 
boundaries of the several streams, bottles cast over at the same spot 
may be carried to opposite sides of the Atlantic. Dr. Schott (pp. 10, 
18; map i.) gives the case of two bottles thrown together into the 
sea a little north and east of St. Paul's Rocks, one being recovered on 
the coast of Sierra Leone and the other on the shores of Nicaragua. 
In the same note of the Appendix (Note 19) in which the details of 
these remarkable drifts are given, reference is made to the possibility 
that under certain conditions seeds may be transported from the 
coasts of North Brazil to the shores of Sierra Leone and Liberia in 
the counter- current formed at certain seasons by the westward 
extension of the Guinea Current. This is probably a rare event, but 
a particular example of bottle- drift is mentioned in this connection. 
With this exception, no opportunity of American seed-drift reaching 
Africa across the tropical latitudes of the North Atlantic is indicated 
by the numerous bottle-drift data at my disposal. 

The Currents of the South Atlantic. — Before proceeding to 
deal with the passage of bottle-drift across the South Atlantic in the 
Main and South Equatorial Currents, I will state the view of the 
currents in this ocean that is adopted in these pages. It seems 
usual to speak in a collective sense of the Southern Equatorial 
Current as dividing, when approaching Cape St. Roque, into the 



60 



PLANTS, SEEDS, AND CURRENTS 



Guiana Current, running northward to the West Indies, and the 
Brazil Current (the smaller of the two), flowing southward along 
the coast of South Brazil. But by some the distinction is made in 
mid- Atlantic between the Main Equatorial Current, which is known 
as the Guiana Current as it approaches the West Indian region, and 
the South Equatorial Current, which is known as the Brazil Current 
when it turns to the south of Cape San Roque. This distinction is 
accepted in this work, and reasons are adduced in Note 18 of the 
Appendix in support of the view that the differentiation already 
exists in mid- Atlantic, the island of Ascension being situated within 
the northern or main stream and that of St. Helena within the 
southern stream. Thus regarded, the Main Equatorial courses 
westward from the Gulf of Guinea between the parallels of 2° N. and 
10° S., whilst the South Equatorial flows west in the Central Atlantic 
between the parallels of 10° and 20° S. 

Though these currents are contiguous in mid-ocean, they have 
different origins and, of course, different destinations. The Main 
Equatorial in its birthplace in the Gulf of Guinea is fed by the 
Guinea Current on its north side, and on its south side by the inshore 
waters of the South African Current. It proceeds north of Cape 
St. Roque to the West Indies, following the trend of the coasts of 
North Brazil, the Guianas and Eastern Venezuela, and gathering 
drift on its way not only from those shores, but from the Amazon, 
the rivers of the Guianas, and the Orinoco. On the other hand, the 
South Equatorial Current may be regarded as fed by the off-shore 
or outside waters of the South African Current, and probably carries 
less African drift. As it crosses the Atlantic it includes St. Helena, 
but not Ascension, within its zone. It is then deflected south of 
Cape St. Roque and flows down the coast of Brazil, finally gathering 
the drift of the Rio de la Plata. Then, blending with the South 
Atlantic Connecting Current, its waters make the return journey past 
Tristan da Cunha to the South-west African coasts. It should, 
however, be noted that some of the waters of the Brazil Current 
probably flow southward to unite with those of the West Wind 
Drift Current, the easterly surface-current of the "Roaring Forties." 
In this manner South American drift would be carried eastward 
towards Australia. 

The Transport of Bottle-drift in the Main Equatorial 
Current. — Having thus described the view of the current system in 
the South Atlantic which is adopted in these pages, I will proceed to 
deal with the indications of the bottle-drift in the case of the Main 
Equatorial Current. Generally speaking, whilst the mass of this 
bottle-drift of the North Equatorial Current strikes the W T est Indies 
to the north of Barbados and St. Vincent, most of the drift of the 
Main Equatorial Current enters the West Indian region to the south 
of those islands. Many of the bottles brought by the southern 
current — about 30 per cent. — are stranded on the coasts of Trinidad 
and Tobago and on the Venezuelan shores of the Gulf of Paria. 
The others are either thrown up on the isles of the Lesser Antilles, 
mainly in the south, or pass between them into the Caribbean Sea, 
where they mingle with the bottle-drift of the North Equatorial 



CURRENTS OF THE ATLANTIC 



61 



Current, and are subsequently dispersed over the shores of the 
Caribbean Sea and of the Gulf of Mexico, reaching in some cases the 
coasts of Florida. 

As indicated by the data at my disposal, the general distribution 
of the bottle-drift of the Main Equatorial Current in the tropics of 
the New World is as follows — 

Places of Recovery oe Sixty Bottles cast Overboard in 
the Main Equatorial Current between the Coast of 
North Brazil and the Vicinity of St. Paul's Rocks 

{The data are obtained from Schott's memoir in three-fourths of the cases and from 
the American charts for the rest) 

The Guianas ...... 5 per cent. 

Trinidad mainly, but including also Tobago 

and the neighbouring coast of Venezuela .31 ,, 
The Lesser Antilles (chiefly in the southern 

islands) 26 

The Greater Antilles (south coasts of Hispaniola, 

Cuba, and Jamaica, including the off-lying 

Cayman Islands . . . . .13 ,, 

The Bahamas . . . . . . 2 „ 

The coasts of Central America (Nicaragua and 

Honduras) . . . . . . 7 ,, 

The Gulf of Mexico (chiefly on the western 

shores) . . . . . . . 11 ,, 

The coasts of Florida . . . . . 5 ,, 

100 

The convergence of the drift towards the limited region comprised 
by Trinidad and its vicinity is conspicuous. But the materials 
stranded in this locality are probably equalled in amount by those 
that are carried swiftly past this region into the Caribbean Sea 
through the Trinidad and Grenada passage to be thrown up ulti- 
mately on the south coasts of Hispaniola, Cuba and Jamaica, on the 
shores of Nicaragua and Honduras, on the western borders of the 
Gulf of Mexico, and on the coasts of the Florida seas. If we separate 
the bottles at their starting-place into two groups, those belonging 
to the St. Paul's Rocks area and those nearer the coast of North 
Brazil, we find that the concentration on Trinidad and its vicinity 
is least marked in the case of the bottles approaching from the 
vicinity of St. Paul's Rocks, the proportion reaching Trinidad from 
this region of the Atlantic being only about 20 per cent., as compared 
with nearly 40 per cent, in the case of those carried past the shores 
of North Brazil. 

But although the great mass of the stream of the Main Equatorial 
Current passes into the Caribbean Sea, there is a subsidiary branch 
which, after skirting the eastern and northern side of the Lesser 
Antilles, unites with the North Equatorial Current and ultimately 



62 PLANTS, SEEDS, AND CURRENTS 



reaches the Bahamas, the north coasts of the Greater Antilles, the 
Florida Strait and the Bermudas. This is the so-called " Antillean 
Stream " to which Dr. Schott particularly refers (p. 13). About 
6 per cent, of the bottles dealt with in the above tabulated results 
represent the part played by this subsidiary current in distributing 
the drift brought by the Main Equatorial Stream to the West Indian 
region. They are those that are stranded on the northernmost islands 
of the Lesser Antilles, on the north coasts of Porto Rico and Hispa- 
niola, and on the off-lying Bahamas. An interesting example is 
afforded in the case of bottle No. 363 in Schott's memoir (p. 13 and 
map ii.). It was dropped into the sea about half-way between Cape 
St. Roque and St. Paul's Rocks, and was recovered on Rum Cay in 
the Bahamas five and a half months afterwards, having accomplished 
the passage of 3078 miles at a minimum daily rate of 18*2 miles. 
Another interesting illustration is afforded by a bottle which, after 
being thrown over about 200 miles off the mouths of the Amazon in 
2° 36' N. and 47° 6' W., was picked up near St. Thomas in 18° 27' N. 
and 64° 49' W. twenty-eight days afterwards, having been carried 
1400 miles at a minimum rate of fifty miles a day (U.S. Chart, North 
Atlantic, May 1909, No. 80). The mingling of the drift of the 
North and Main Equatorial Currents in the region between the 
Bahamas and the Greater Antilles is a point of great interest in the 
distribution of seeds by currents. 

The South Equatorial and the Brazil Currents. — Being, as 
I have shown above, the continuation of the South Equatorial 
Current that crosses the South Atlantic about the latitude of St. 
Helena, the Brazil Current proceeds southward, following the trend 
of the coast, part of its waters reaching the estuary of La Plata, the 
greater portion, however, being deflected eastward between the 30th 
and 35th parallels, where they join the South Atlantic Connecting 
Current that runs eastward to the South African coast. In this way 
it is possible for drift to make a complete circuit of the South Atlantic, 
since on approaching the South African coast the materials not 
stranded would be borne northward in the South African Current, 
those in the inshore waters ultimately getting into the Main Equa- 
torial Current, and those in the off-shore waters coming within the 
influence of the South Equatorial Current. The bottle-drift data at 
my disposal for this ocean are scanty, but they illustrate the circular 
play of the currents, and they show that whilst extra-tropical South 
Africa may supply drift to tropical Brazil, it may receive drift from 
the same region. One of the most interesting records of bottle-drift 
ever published in this connection is concerned with a bottle that was 
thrown into the Indian Ocean off the coast of Natal and was recovered 
on the shores of Brazil in lat. 17° 30' S. The bottle just mentioned 
must have doubled the Cape, and in its subsequent transport by the 
South African and South Equatorial Currents we have an illustration 
of the passage of drift from extra-tropical South Africa to tropical 
Brazil (further details of this remarkable drift are given a page or 
two later). 

But to understand how tropical Brazil may in its turn supply 
drift to South Africa it will be necessary to examine the working of 



CURRENTS OF THE ATLANTIC 63 



the Brazilian Current, as exemplified by bottle-drift in the fourth 
map and on p. 20 of Schott's memoir. It is not a rapid stream, 
its rate being twelve to twenty miles a day, and in consequence it 
is liable to a set-back within the tropics during the southern winter 
owing to the influence of the prevailing South-east Trade. In this 
manner, no doubt, some of its drift is carried back round Cape 
St. Roque and mingles with that of the Main Equatorial, an event 
which actually occurred in the case of some bottles referred to in 
this memoir. But for this occasional set-back, the current would 
have a steady flow south. Yet the bottle-drift dealt with by Dr. 
Schott in this connection only tells part of the story. Though 
many bottles are cast up on the coasts as far south as Montevideo, 
we know nothing of those that must have been deflected eastward to 
be carried across in the South Atlantic Connecting Current to the 
west coasts of South Africa, where in the great majority of cases 
they could never be recovered. Their track across the Atlantic 
would curve south to about the 40th parallel, and would then be 
represented by that laid down by Dr. Schott in his map for a bottle 
which, after being cast over in about 41° 30' S. and long. 32° W., 
was recovered near the Cape of Good Hope. 

The Current-connections of the South Atlantic with the 
Indian and Pacific Oceans, as Illustrated by Bottle-drift. — 
This is a matter of importance, since upon it depends the possibility 
of the intrusion of seed-drift into the South Atlantic from the oceans 
on either side of it. Taking, first, the connection with the Indian 
Ocean, Dr. Schott gives the tracks of two bottles that doubled the 
Capes of Agulhas and Good Hope in their passage westward into the 
South Atlantic. One of them, after being dropped overboard less 
than a hundred miles south of Port Elizabeth, was cast up on the 
west coast of Cape Colony in about lat. 33° S. (maps 4 and 5). The 
other accomplished a much longer passage. Having been thrown 
into the sea off the coast of Natal in lat. 29° 24' S. and long. 33° E., 
it was carried by the Agulhas Current round the southern extreme of 
the continent, whence it passed into the South African Current and 
from there into the South Equatorial Current, being ultimately 
stranded on the coast of Brazil in lat. 17° 30' S. This involved a 
drift of about 4120 miles, a period of 612 days elapsing between the 
start and the recovery of the bottle (pp. 19, 27 ; maps iv. and v. ; 
track 6). 

With regard to the connection between the South Pacific and 
South Atlantic Oceans round the Horn, the data at my disposal 
indicate that it occasionally occurs. Most of the bottles dropped off 
Cape Horn are drifted before the Westerly Winds to Australia — as 
illustrated by the tracks of four bottles mentioned by Schott and 
others which are specially dealt with in Chapter XIII. In the same 
chapter allusion is made to the figurehead of a ship burnt at sea in 
these latitudes which was also recovered in Australia. In none of 
these cases did the drifting object double the Horn; but Schott 
gives the track of a bottle in map vi. which was cast over in about 
lat. 54° 20' S., less than a hundred miles off the west coast of Tierra 
del Fuego, and drifted in the Cape Horn Current to the Falkland 



64 PLANTS, SEEDS, AND CURRENTS 



Islands. Had the bottle missed these islands, it would have been 
borne north-east in the same current, and, getting within the influence 
of the Brazilian Current, as it is deflected eastward, would have 
entered the circulation of the South Atlantic. 

The Difficulties Connected with the Drifting Rates of 
Bottles across the Atlantic — We come now to the discussion of 
the time occupied by the drifting bottles in crossing the Atlantic, 
either from the American or from the European and African side of 
the ocean. In the charts the average drift per day is calculated up 
to the date of the recovery of the bottle. This, as is pointed out by 
the compiler of the American charts, must be in most cases less than 
the actual drift-rate, since " no allowance is made for the time, 
probably often considerable, during which the bottle lay undisturbed 
on the beach." So also Schott observes (p. 10) that the calculated 
velocities are merely minimum values, which could only in the rarest 
cases correspond approximately to the true rate. This naturally 
introduces an element of great uncertainty; but, if we assume that 
20 or 25 per cent, of the bottles were recovered without great delay, 
it is likely that we shall obtain an approach to the average drift-rate. 
The results here employed have been calculated on this basis. As 
before observed, the Prince of Monaco adopted a similar method in 
estimating the mean velocity of his floats, usually taking the average 
of the fastest fourth or third, except when the data were few, when 
he selected the most rapid example. 

After handling the data during a long period it is not difficult to 
recognise sets of results which possess a critical value. One of these 
is given below in connection with five bottles dropped at the same 
date into the sea in the vicinity of Cape Hatteras. Here it is not 
hard to distinguish between the bottles that were quickly recovered 
and those that had been lying a long time on the shore. It rarely 
happens that we can exclude the element of uncertainty altogether. 
But it is manifest, when the bottle is picked up afloat off a coast by 
fishermen, or when the finder remarks that as it lay on the sand it 
had all the appearance of having been washed up by the last tide, 
that we are on relatively safe ground. Instances of both these 
occurrences are mentioned in the following pages. As an example 
of the great range of the periods elapsing between the start and the 
recovery of the bottles I will cite the case of nine bottles which 
crossed the Atlantic from the Florida region to the coasts of Europe. 
Since the periods varied between eleven months and three years, it 
is obvious that a year and more may be spent by a stranded bottle 
before it is found. However, in the case of some of these belated 
" finds " one may suspect that there has been a long sojourn in the 
still waters of the Sargasso Sea, the notable gathering-place of the 
wreckage of the North Atlantic. As in the instance of some bottles 
cast up on the Azores, where an interval of several years elapsed, 
one may seek here for an explanation of the great delay in the re- 
covery. Such a case as is mentioned by Purdy in the Columbian 
Navigator for 1839, where a bottle dropped overboard off Madeira in 
June 1825 was picked up ten years after on the Turks Islands, may 
be placed in this category. The table subjoined is intended to illus- 



CURRENTS OF THE ATLANTIC 65 



trate the critical value of the data supplied by a number of bottles 
cast into the sea at the same place and at the same time. 

Five Bottles put Overboard together prom the s.s. "Cherokee" about a 

HUNDRED MILES TO THE NORTH OF CAPE HaTTERAS ON DECEMBER 21, 1905 



(Results taken from the North Atlantic Pilot Chart for December 1908, published 
by the U.S. Hydrographic Office.) 



Place of Recovery 


Interval in Days 


Total Drift in 
Nautical Miles 


Average Drift in 
Miles per Day 


Bermuda . . . . . 


103 


520 


5-0 




168 


520 


3-1 


West coast of Scotland 








(56°30'N.) . . . . 


390 


3040 


7-8 


Shetland Islands 


466 


3210 


6-9 


Norway, near the North 








Cape in lat. 70° 20' N., 








long. 22° 58' E. . . 


416 


4250 


10-2 



Here it is evident that the three bottles with the longest drifts 
followed the same track until near the Scottish coast, and that the 
one recovered in the north of Norway must have been found soon 
after it had been stranded. 

The Drifting Rates of Bottles across the Atlantic. — In the 
following table (p. 66) I have elaborated most of the data at my dis- 
posal that concern the drifting rates of bottles across the North and 
the Equatorial Atlantic. The subsequent remarks relate to the 
different passages, beginning with the traverse from the Florida 
Strait and the neighbouring West Indian waters to the coasts of 
Europe. These are the most interesting of the bottle-drift records, 
since Europe is here brought into touch with a locality that not only 
receives drift from the entire West Indian region, but is also the 
recipient of drift transported by the North and Main Equatorial 
Currents from tropical Africa, as well as from the coasts of the 
Guianas and North Brazil. The traverse of the ocean from the 
European and African side to the New World is then dealt with, and 
the discussion ends with some general conclusions relating to the 
average periods taken by bottle-drift in performing the various 
passages and traverses of this ocean. 

The Drift-rates from the West Indies to the Coasts of 
Europe. — The stages in this traverse of the North Atlantic are indi- 
cated in the table given on p. 66, and it has already been established 
in a previous table that quite four-fifths of the bottles are stranded 
on the Scottish, Irish, English and French coasts. Whilst the 
shortest passage was performed in about eleven months, the average 
period was about fourteen months. The quickest drift was that of 
a bottle which reached the Irish coast from off the north coast of 
Hispaniola in 337 days, a passage of 4140 miles (U.S. Pilot Chart, 
N. Atlantic, May 1909). It seems unlikely that the traverse from 
off Cape Hatteras could be often accomplished by a bottle in less 

F 



66 PLANTS, SEEDS, AND CURRENTS 



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CURRENTS OF THE ATLANTIC 67 



1 


1 


I 


See Note 18 of 
Appendix 


1 


1 


1 ' 


1 


1 


Partly estimated 


Partly estimated 


ob 

CO 

oo 


cp 

CM 
i— i 

tH 
CM 

CM 
i— t 


16-8; 12-0: 11-2; 
10-6 


1 


20-0; 19-8 


CM 
t- 

<M 

cb 

CM 
CM 

Th 

CO 


19-8 


50-0; 43-5; 36-2; 
34-2 


16-8 


1 


1 


do 


12-8 


12-6 


20-0 


20-0 


30-0 


20-0 


40-0 


17-0 


30-0 


34-0 


c 
© 


CO 

o 

CM 


CO 

o 


1 


001 


CD 


o 


lO 
CM 


co 
oo 


CO 
00 


GO 


3500 


2600 


1300 


3200 


2000 


2000 


1000 


1000 


3200 


2500 


4000 




CO 


CM 
CM 




CO 


o 
i—i 




C5 




1 


1 


Vicinity of Madeira and the 
Canary Islands 


© o 
© ■ 

is'© 

> Jo" 


About half-way between the 
Cape Verde Islands and the 
West Indies, 13°-19° N. lat. 


Vicinity of Ascension Island 


Vicinity of St. Paul's Rocks 
(0°-7° N. lat.; 22°-32° W. 
long.) 


Between St. Paul's Rocks 
and Cape St. Roque 


About half-way between St. 
Paul's Rocks and Trinidad 


Off the Amazon estuary 


Off the Amazon estuary 


Gulf of Guinea 


Gulf of Guinea 


in the North Equatorial 
Current between 10° and 
20° N. lat. 


To the West Indies in 
the direction of Trinidad 
in the Main Equatorial 
Current 


To the coast of Florida 
by the Caribbean Sea and 
Gulf of Mexico 


To the vicinity of Cape 
St. Roque in mid-stream 


To the West Indies 
(Trinidad) 



68 PLANTS, SEEDS, AND CURRENTS 



than a year, though the shortest period would be rather over ten 
months. In Note 16 of the Appendix reference is made to a derelict 
which drifted from Baltimore Bay to the Hebrides in a little over 
ten months, but about half the time was spent drifting about within 
a small area in mid-ocean. A critical value belongs to a rate of 
eight miles which is given by Schott (p. 11, map ii.) for a bottle that, 
after being thrown into the sea about 350 miles north-east of Cape 
Race, was recovered on the Isle of Skye. According to the finder, it 
appeared to have been thrown up at the last flood-tide. 

The uniformity in the average daily rate of eight to nine miles across 
the North Atlantic is remarkable, and this brings us to record that 
the average rates computed by the Prince of Monaco for his floats 
in the eastern half of this ocean are only half this amount. His 
observations, as we have seen, were made on a line drawn from the 
Azores to the Banks of Newfoundland, as well as in localities to 
the east and north of that line; and he places the average drifting 
rate to the shores of Europe, ranging from Norway to Portugal, 
at four to five miles a day. This discrepancy, however, is capable 
of explanation, and I imagine that it may be largely discounted. 
It is evident that the Prince of Monaco mainly based his rates on 
the experiments made between June and July 1887, between New- 
foundland and the Azores and to the north of that group. On the 
other hand, the data tabulated above for this traverse are supplied 
by records that cover a long period of years, and in this manner the 
disturbing influences retarding the eastward flow of the surface- 
currents during a particular year or season have been eliminated. 
To such retarding influences experiments made in the same season 
might be exposed. It is noteworthy that in the experiments of the 
Prince of Monaco in 1886, when the floats were cast overboard at 
distances ranging from 400 to 700 miles from the Portuguese and 
French coasts, more rapid velocities were obtained. The five fastest 
rates of eleven bottles stranded on the coasts of Portugal and West 
Spain gave a mean of 7*15 miles a day. So, again, the mean of the 
seven quickest rates for twenty-four bottles recovered on the west 
coast of France was 6*67 miles a day. The Prince of Monaco's floats 
were as a rule deeply submerged, and were thus much less likely to 
be influenced directly by the wind than the ordinary floating bottle. 
Yet the retarding effect of contrary winds might be counterbalanced 
by the acceleration produced by fair winds. 

The Drifting Rates from off the Coasts of Europe to the 
West Indies. — In making this traverse bottle-drift seems to travel 
at about the same average speed as in the case of that brought to 
Europe in the Gulf Stream — namely, eight to nine miles a day, the 
time occupied being usually sixteen to seventeen months. But the 
rate varies greatly in different portions of the traverse. It is in the 
passage south from European latitudes to the region of the North 
Equatorial Current that the slowest progress is made. From the 
data supplied by a number of bottle-drifts in the American charts 
it is evident that the average daily rate for this passage is only 
four or five miles. On the other hand, as shown in the table, bottles 
starting from the vicinity of the Canary Islands are carried into the 



CURRENTS OF THE ATLANTIC 69 



North Equatorial Current, and accomplish the traverse to the West 
Indies at an average rate of nearly nine miles a day ; whilst farther 
south, in the latitude of the Cape Verde Group, the trans-oceanic 
passage is performed at an average speed of nearly thirteen miles 
a day. These conclusions are confirmed by the results of the Prince 
of Monaco's experiments in 1886 opposite the coasts of France and 
Portugal along the meridian of 17° 40' W. From this region the 
daily drifting rate to the Canary Islands is placed at four and a half 
miles and to the West Indies at ten and a half miles. Daussy, whose 
paper on bottle-drift in this ocean (Comptes Rendus, 1839, p. 81) 
has before been mentioned, places the daily speed of bottles in the 
equatorial zone of the North Atlantic at eight to ten miles. 

An interesting case is recorded in the table of a bottle which 
accomplished the whole of the passage from a point about 260 miles 
off the south-west of Ireland to the south-eastern extremity of the 
Bahamas in a minimum time of 597 days (U.S. chart, December 

1908, bot. 85). The greatest velocity referred to in the table in 
connection with the passage in the North Equatorial Current was 
attained by a bottle that travelled from mid- Atlantic to the West 
Indian region at an average speed of 16-8 miles a day. It per- 
formed the passage from 9° 51' N. lat. and 32° W. long, to St. Vincent, 
a distance of 1660 miles, within ninety-nine days (U.S. chart, February 

1909, bot. 48). It is worth noting that the derelict American schooner 
Alma Cummings was drifted at the rate of sixteen miles a day from 
a position 600-700 miles west of the Cape Verde Islands to the Panama 
Isthmus (see Note 15 of Appendix). A critical value attaches itself 
to a bottle that was transported in the North Equatorial Current 
from a position south of Cape Verde Group (lat. 14° 1' N. ; long. 
25° 2' W.) to the Grenadines in 169 days, which gives a daily rate 
of about thirteen miles. There could have been but little loss of 
time in its recovery, since it was found afloat off the coast (see 
Nautical Magazine for 1852, bot. 42, and 1853, p. 437). 

The individuality of the North Equatorial Current is not always 
sufficiently recognised. It is something more than the North-east 
Trade-drift. Between the parallels of 10° and 20° N. it is illus- 
trated by about fifty bottle-tracks in Schott's maps and by nearly 
half that number in the American charts examined, as well as by 
about a dozen other examples from other sources. The part that 
it takes in the circulatory movement of the waters of the north 
Atlantic is strikingly exemplified in the results of the Prince of 
Monaco's experiments in the temperate latitudes of the north-east 
Atlantic, almost a tenth of the floats recovered having been found 
in the West Indian region. All the months of the year are repre- 
sented in the records at my disposal, and there is not a single instance 
of a drift to the eastward in these latitudes (10°-20° N.) in the open 
ocean. Always there is a steady flow to the west, with but little 
of the " southing " one would expect in a mere trade- wind current. 

Drift-Rates from Tropical Africa to Brazil and the West 
Indian Region in the Main Equatorial Current. — A much 
greater velocity is regularly displayed by the Main Equatorial 
Current as it traverses the Atlantic from the Gulf of Guinea to the 



70 PLANTS, SEEDS, AND CURRENTS 



coasts of North Brazil, thence proceeding northward past the Guianas 
to the West Indies. From the Admiralty Sailing Directions, Laugh- 
ton's Physical Geography, and other works of reference, it is evident 
that very high velocities, even of sixty miles a day, are at times 
attained by this current on its way to Cape St. Roque. It is prob- 
able, however, that an average rate of twenty to thirty miles is near 
the truth. In the latter part of its course, along the coasts of North 
Brazil and the Guianas, it nearly doubles its speed, flowing usually 
from thirty to fifty miles a day and occasionally as much as seventy 
or eighty miles. 

The behaviour of the drifting bottle is quite in agreement with the 
known great speed of this powerful current. In Note 1 of the 
Appendix the data are discussed; and it is shown that whilst in 
the slacker water in the vicinity of St. Paul's Rocks and Ascension, 
that is, in the northern and southern portions of the current, the 
bottles are carried along at a rate of about twenty miles a day, in 
the centre of the stream, as it concentrates between St. Paul's Rocks 
and Cape St. Roque, an average speed of thirty miles is attained. 
From what has been said it would be expected that during the 
remainder of the passage along the South American seaboard to 
the West Indian region the speed of bottle-drift would respond to the 
increase in the velocity of the current as it sweeps past the coasts 
of North Brazil and the Guianas. This expectation is fully justified 
in the facts given in the note, where a daily rate of between thirty 
and fifty miles, and averaging forty miles, is indicated. It may be 
inferred from these data that, starting from the Gulf of Guinea, a 
bottle would require an average period of twelve weeks to reach 
the vicinity of Cape St. Roque and of seventeen weeks to reach 
Trinidad. It is, however, not improbable when the current runs 
with unusually great speed that the traverse to the Brazilian coast 
may be performed in as little as two months. 

The Drifting Rate of Bottles from off the Amazon Estuary 
to the Coast of Florida. — This establishes an interesting connec- 
tion, since we already know how long a period is usually required 
by bottle-drift for the passage from Florida to the shores of Europe, 
namely, fourteen months; and we shall thus be able to determine 
the time that would be required for Amazon drift, as typified by the 
floating bottle, to reach our coasts. As previously remarked, the 
track assigned in both the American and German charts to bottles 
that arrive in the Florida seas from latitudes in the tropical Atlantic 
south of 10° N. lies across the Caribbean Sea and through the Straits 
of Yucatan. The data for three bottles that accomplished this 
passage from off the Amazon to Florida waters are supplied in 
Note 1 of the Appendix. It is there inferred that this traverse 
of 3200 miles would be performed in about six months at the rate 
of seventeen miles a day, from which it may be concluded that as 
a rule the passage of Amazon drift to Europe would occupy twenty 
months. 

The Drift-Rates in the Brazil Current. — The Brazil Current 
has been before alluded to as an extension of the South Equatorial 
Current. Its velocity is usually stated to be from twelve to twenty 



CURRENTS OF THE ATLANTIC 71 



miles a day, which is greater than that displayed by numerous 
bottle-drifts given by Schott, who says that more than ten miles a 
day was seldom indicated (pp. 19, 20, map iv.). The longest passage 
was that of a bottle which was carried about 1600 miles from opposite 
Bahia to the vicinity of Montevideo at a minimum daily rate of 
about ten miles. Many of the bottles, however, were stranded on 
the coasts further north. 

General Results of the Bottle -Drift Data for the Atlantic 

AND THEIR APPLICATION TO THE DlSPERSAL OF SEEDS BY CURRENTS. 

In order to draw from the foregoing discussion some conclusions that 
may be of practical value in the consideration of the dispersal of 
seeds by currents in the Atlantic, I have given below a few general 
results relating to the average periods taken by bottle-drift in accom- 
plishing the various traverses and passages of this ocean. 

Results foe the Times occupied by the Drifting Bottle in crossing 
the Atlantic in Northern and Equatorial Latitudes 



(A) From the Florida and neighbouring West Indian 

region to the shores of Europe by the Gulf 
Stream route. 

(B) From off the coasts of Europe to the West 

Indies (Lesser Antilles and the Southern 
Bahamas) by the Canary and Cape Verde 
groups and in the North Equatorial Current. 

(C) From the Gulf of Guinea to the West Indies 

(South of Barbados) in the Main Equatorial 
Current. 

(D) From the Gulf of Guinea to the nearest coast 

of Brazil in the Main Equatorial Current. 



(E) From off the Amazon estuary to Florida by 

the Caribbean Sea and the Straits of Yucatan 
in the Main Equatorial Current. 

(F) From off the Amazon estuary to the shores of 

Europe by the Caribbean Sea, the Yucatan 
and Florida Straits, and the Gulf Stream 
route. 

(G) The circuit of the North Atlantic from the 

Florida region to the Lesser Antilles and the 
Southern Bahamas by the Gulf Stream route 
and in the North Equatorial Current. (For 
the return to the Florida seas 160 days should 
be added for the usual completion of the 
route by the Caribbean Sea and the Gulf of 
Mexico, and 100 days for its completion by 
the short passage through the Northern 
Bahamas.) 



4000 miles at 9-2 miles a day 
in 435 days, or about a 
year and two months. 

4500 miles at 9 miles a day 
in 500 days, or a year and 
4 J months. 



4000 miles at 34 miles a day 
in 118 days, or about 4 
months. 

2500 miles at 30 miles a day 
in 83 days or 12 weeks, but 
under exceptionally favour- 
able conditions in 60 days. 

3200 miles at 17 miles a day 
in 188 days, or about 6 
months. 

7200 miles at 11 \ miles a day 
in 623 days, or about 20 
months. Calculated from 
results A and E. 

8500 miles at about 9 miles 
a day in 935 days, or about 
2\ years. Calculated from 
results A and B. 



The first matter in connection with these results that needs further 
discussion is the time occupied in the circuit of the North Atlantic. 



72 PLANTS, SEEDS, AND CURRENTS 



For obvious reasons it would be very difficult to demonstrate this 
circuit for any particular bottle. The nearest approach to the 
complete record is that of the bottle, already alluded to, which was 
picked up on the west coast of Ireland thirty-four months after it 
had been cast over to the westward of the Cape Verde Islands. It 
is easy to construct the circuit piecemeal fashion. A striking instance 
is afforded by two bottles which in one case reached the South- 
eastern Bahamas from off the coast of Ireland, and in the other 
reached the Irish coast from the South-eastern Bahamas, the track 
of the North Equatorial Current being followed in the first case 
and the Gulf Stream route in the second case. The data for these 
observations are given in Note 20 of the Appendix ; but it may here 
be stated that the total period, calculated up to the dates of the 
recoveries, amounts to 934 days, and the average drifting rate to 
nearly ten miles a day. This period is identical with that given 
under G in the above table, though to that period about a hundred 
days should be added for the passage from the South-eastern Bahamas 
to the Florida seas. . . . Derelicts would probably perform the 
circuit of the North Atlantic in a shorter time. Whilst the circuit, 
beginning and ending with the Florida seas, would require about 
three years for a bottle, it might not require more than two years 
for a derelict. The Alma Cummings, when drifting in 553 days from 
off Cape Hatteras to the Panama Isthmus, nearly described the 
circle; but since the wreck was deflected south to the westward of 
the Azores, its passage was somewhat shortened (see Note 15). 

The Distribution in the West Indian Region of Seed-drift 
Brought by the North and Main Equatorial Currents as 
illustrated by Bottle-drift. — By following the indications sup- 
plied by the floating bottle in this matter we shall be determining 
the distribution over the West Indian region of the seed-drift brought 
in the North and Main Equatorial Currents. Bottles arriving in 
the first-named current strike the South-eastern Bahamas and the 
Lesser Antilles, in the last locality usually north of Barbados. Of 
those reaching the south-eastern islands of the Bahamas the great 
majority are stranded in that neighbourhood; but a few, as is shown 
in Note 13, are carried in the prevailing westerly drift-current to the 
Florida seas. However, as is indicated in the table on p. 57, only 
about 25 per cent, of the bottles brought to the West Indian region 
in the North Equatorial Current are beached on the Bahamas. 
About 10 per cent, are carried beyond that group and are thrown 
up on the north coasts of the Greater Antilles. All the rest strike 
the line of the Lesser Antilles, but generally north of Barbados, 
and more than half of them are stranded on those islands. The 
survivors (about 27 per cent, of the original total) pass between 
the islands into the Caribbean Sea. Most of them are stranded on 
the south coasts of the Greater Antilles and on the shores of Central 
America; but a few (amounting to about 7 per cent, of the original 
total) are carried through the Straits of Yucatan into the Gulf of 
Mexico and are ultimately beached on the shores of that gulf and 
on the coasts of Florida. Several examples are given in the charts 
of bottles that illustrate this circuitous route from the Lesser Antilles 



CURRENTS OF THE ATLANTIC 73 



across the Caribbean Sea and by the Gulf of Mexico to Florida. 
The length of the passage is about 2000 miles, and the indications 
are that about 160 days would be required for its accomplishment. 

The distribution over the West Indian region of the seed-drift 
brought by the Main Equatorial Current is well exemplified by the 
disposal of its bottle-drift as described on p. 61. After depositing 
5 per cent, of its burden on the shores of the Guianas, it leaves 31 per 
cent, on Trinidad and Tobago and on the neighbouring Venezuelan 
coasts, and 26 per cent, on the islands of the Lesser Antilles, chiefly 
in the south, only 2 per cent, reaching the Bahamas. The remainder 
(36 per cent, of the total) breaks through the islands and passes into 
the Caribbean Sea, more than half being thrown up on the south 
coasts of the Greater Antilles and on the shores of Central America, 
whilst the survivors, after passing through the Straits of Yucatan, 
are stranded on the shores of the Gulf of Mexico and on the Florida 
coasts. 

The mingling in the Caribbean Sea of drift brought by the North 
and Main Equatorial Currents is well exemplified in the remarks 
above made. Whether brought by the one current or by the other, 
the drift, after it enters this sea, has the same distribution on the 
south coasts of the Greater Antilles, on the shores of Central America 
and of the Gulf of Mexico, and on the Florida coasts. But the 
mingling of the drift begins off the Atlantic coasts of the Lesser 
Antilles and in the southernmost of those islands. In the first case, 
the Antillean Stream, referred to on a previous page, commences the 
mixing process in its north-westerly course towards the Bahamas. 
In the second case, although the island of Barbados usually divides 
the main streams of the two equatorial currents, there is not infre- 
quently an overlapping of the currents in its vicinity with, as the 
result, an intermingling of their drift in the southern islands of the 
Lesser Antilles. 

The meeting in West Indian waters of seed- drift brought by these 
two great equatorial currents from the North and South Atlantic 
is a matter of great interest for the student of plant distribution. 
It is a subject that attracted the attention of Dr. Schott when dis- 
cussing the bottle-drift data of this region (p. 11). The importance 
of this fact is obvious. Whilst the North Equatorial Current brings 
to the West Indies the sweepings of the Atlantic seaboard of 
North America, and of Southern Europe and North-west Africa, 
through the respective agencies of the Gulf Stream and of the Portu- 
guese or North African Current, the Main Equatorial Current carries 
to the same region the sweepings of both sides of the South Atlantic, 
from tropical West Africa, South-west Africa, Brazil, and the 
Guianas. 

The Burden of the Main Equatorial Current. — This current 
bears westward not only drift from the shores and great rivers of 
tropical Africa, but also drift which it has received from the South 
African Current. This current has previously swept the shores of 
South-west Africa, and has caught up drift brought across by the 
South Atlantic Connecting Current from the Brazil Current on the 
other side of the ocean, materials derived from the Rio de la Plata 



74 PLANTS, SEEDS, AND CURRENTS 



and from the shores and estuaries of Brazil south of Cape St. Roque. 
The burden carried westward by the Main Equatorial Current must, 
indeed, be a motley one. The seed-drift of the rivers of two conti- 
nents, including some of the largest rivers of the world, contribute 
to its freight. It bears westward towards Brazil drift of the Plate, 
the Congo, and the Niger; and as it sweeps northward to the West 
Indian region it gathers materials from the Amazon, the rivers of 
the Guianas, and the Orinoco. 

But the possible sources of seed-drift do not end here, since the 
Main Equatorial Current may receive accessions from the Indian 
and Pacific Oceans. The Atlantic is not a closed ocean to the south. 
It has already been shown that bottle-drift from the east coast of 
Africa can double the Cape and reach the shores of Brazil, and 
that materials from the Pacific side of Fuegia can double the Horn 
and reach the Falkland Islands. In the first case the Indian Ocean 
is tapped as a source of seed-drift. In the second case we have 
the possibility that the drift from New Zealand and the islands of 
the Southern Ocean, after it strikes the coasts of South Chile and the 
western shores of Fuegia, may at times double Cape Horn and get 
within the influence of the currents of the South Atlantic. (The 
bottle-drift of high southern latitudes is dealt with in Chapter XIII.) 

The Island of Trinidad as a Centre of Drift Dispersal. — 
Next to the Florida Sea, the gathering-place of much of the floating 
seed-drift of the West Indian region before beginning its transatlantic 
passage in the Gulf Stream, there is no locality so interesting as a 
drift-centre as the island of Trinidad. From the standpoint of the 
dispersal of plants by currents, it is the connecting centre or junction 
of the lines of dispersal that converge from the Atlantic side and 
diverge on the West Indian side. As shown by the floating bottles, 
it is the Main Equatorial Current that principally piles up drift on 
its beaches, drift from tropical West Africa and from the north-east 
seaboard of South America, though at times, as indicated below, 
drift also reaches it from the North Atlantic through the North 
Equatorial Current. Whilst materials from the South American 
mainland north of Cape St. Roque doubtless greatly predominate, 
including, as they do, the drift of the Amazon, of the rivers of the 
Guianas, and of the Orinoco, yet materials from the West African 
rivers, the Niger and the Congo, as well as from the shores of the 
Gulf of Guinea, must be represented. 

The bottle-drift data relating to this locality are worthy of further 
remark. It has already been shown that about thirty of every 
hundred bottles recovered after being thrown into the Main Equatorial 
Current between the coast of North Brazil and St. Paul's Rocks 
reached Trinidad. Much of the Amazon drift, as observed below, 
is cast up on the shores of this island. Five out of sixteen bottles, 
that were recovered after being dropped overboard off the Amazon 
estuary, were stranded on Trinidad. Dr. Schott (pp. 12, 14) dwells 
on the very large number of records of drift bottles that were returned 
to the " Deutsche Seewarte " in Hamburg from the east coast of 
this island, almost all of them arriving there from the south-east 
and east-south-east, less than 10 per cent, coming from the east or 



CURRENTS OF THE ATLANTIC 75 



north-east, or from latitudes north of 10° N. within the zone of the 
North Equatorial Current. It may be, therefore, truly said that on 
the beaches of Trinidad we find sampled all the seed-drift that reaches 
the West Indian region, and, in fact, the New World. 

The Transport of Amazon Drift to the West Indian and 
Florida Regions and Probably also to Europe. — The transport 
of Amazon drift to the West Indian Islands has long been surmised, 
and in this connection we may quote the remark of Sir D. Morris 
that the general characters of the drift on the south coast of Jamaica 
point to a source in the Orinoco and the Amazon (Nature, January 31, 
1889). The vegetable drift brought down in such quantities by the 
Amazon soon gets into the rapid stream of the Main Equatorial 
Current and is distributed over the West Indian region. " The 
waters of the Amazon," writes Laughton in his Physical Geography 
(1873, p. 188), " at first set to the north-east, but they soon incline 
to the northward, and falling into the strength of the current are 
swept away to the north-west." Bates observed Amazon drift, 
more particularly the fruits of Manicaria saccifera, which are so 
characteristic of West Indian beach-drift, about 400 miles to the 
north of the mouth of the estuary (The Naturalist on the River Amazons, 
1864, p. 461). The American and German bottle-drift charts clearly 
indicate the mode of distribution of such floating fruits and seeds 
and the tracks that would usually be followed. I here give the 
places of recovery of sixteen bottles thrown into the sea between 
200 and 400 miles north and east of the Amazon estuary, the data 
being mainly supplied by the American charts. Three were cast 
up on the coasts of the Guianas, five on Trinidad, one on the adjacent 
island of Tobago, one on the neighbouring Venezuelan shores, three 
on the Lesser Antilles (between Grenada and the Virgin Islands), 
one on the shores of the Gulf of Honduras, and two on the east 
coast of Florida after passing through the Florida Straits. One of 
the records relating to the Florida coast should be specially men- 
tioned here, since my authority is an old newspaper cutting dating 
back, perhaps, to the closing years of last century. A bottle thrown 
over from the Prince Eugene on March 11, about 300 miles north-east 
of the Amazon estuary, was picked up 279 days afterwards on the 
east coast of Florida, in lat. 27° 30' N. The captain was informed 
by letter from the Hydrographic Office in Washington that it had 
performed a passage of 3320 miles. 

In establishing this link by bottle-drift between the estuary of 
the Amazon and the Florida seas we indicate the probability of fruits 
and seeds of the Amazon drift being transported to the shores of 
Western Europe. It is in the neighbourhood of the Florida Straits 
that West Indian drift gathers before starting northward on its 
rapid journey through the straits towards Cape Hatteras and thence 
across the Atlantic. The data enable us to place the period needed 
for this long passage from the Amazon to Europe at about twenty 
months, allowing six months for the first stage ending with the 
Florida Straits, and fourteen months for the Atlantic traverse. It is 
on the same grounds — namely, that drift from the Main Equatorial 
Current reaches the Florida coasts and that drift from the Florida 



76 PLANTS, SEEDS, AND CURRENTS 



Straits is stranded on the shores of Europe, that Dr. Schott (p. 13) 
assumes the presence of water from the southern hemisphere in our 
northern seas. It is true that no bottle from off the mouths of the 
Amazon seems to have been found on the coast of Europe ; but we 
have the record of a bottle, referred to on p. 59, that was dropped 
into the Caribbean Sea about 100 miles from the south coast of 
Jamaica in the direct track of the Main Equatorial Current and was 
recovered on the Irish coast. The first part of the passage from the 
coast of Brazil would be indicated by the track of a bottle that 
reached the Cayman Islands from Ceara, north-west of Cape St. 
Roque (Savage English, Kew Bull, 1913, p. 370). 

But the demonstration of this link between the Florida Straits 
and the Amazon estuary may mean even more, since the Main 
Equatorial Current before quitting the Gulf of Guinea would have 
gathered drift from the West African coasts and from the estuaries 
of the Niger and the Congo. It is therefore not unlikely that even 
West African drift might find its way by this circuitous route to the 
shores of Europe. The bottle-drift data indicate that if Amazon 
drift can reach European waters in twenty months that from the 
Congo would require two years. Reference has several times been 
made to a bottle which was found on the Irish coast thirty-four 
months after it had been thrown over to the westward of the Cape 
Verde Islands, having crossed and recrossed the Atlantic in the 
North Equatorial Current and in the Gulf Stream. But I possess 
no bottle-drift data bearing directly on the possibility of drift being 
carried from the Gulf of Guinea and the two great rivers of equatorial 
West Africa to the coasts of Europe. There is, however, the ex- 
tremely interesting observation of General Sabine, where casks of 
palm oil from a ship wrecked on the borders of this gulf are stated 
to have been drifted ashore in the following year at the extreme 
north of Norway, and there is the case of a bottle thrown over from 
the Lady Montague, two and a half leagues north-east of Ascension, 
which was found afloat off the coast of Guernsey 295 days afterwards. 
There are, however, serious difficulties connected with the first case, 
and as regards the second it seems incredible that a bottle could 
twice traverse the Atlantic, in equatorial and north temperate lati- 
tudes, in less than ten months. Both of these exceptional cases 
are dealt with in Notes 25 and 26 of the Appendix. 

The Balance of the Account between the Old and the 
New World. — It is an error to place an equal value, as De Candolle 
does in his Geographie Botanique (pp. 763-4, 1855), on the work of 
the Gulf Stream and of the Equatorial Currents in transporting 
seeds to the Old World and in carrying them to the New World in 
a suitable condition for germination. He considers that the seed- 
drift would be carried to the Gulf of Guinea from the tropics of the 
New World in that portion of the Gulf Stream that bends south 
past Europe and North Africa to the Canary Islands. There is no 
support given to this view by the numerous bottle-drift data at my 
disposal. All such drift, when it approaches the vicinity of the 
Cape Verde Group, is deflected westward and is borne in the North 
Equatorial Current to the West Indies. There is no approach to 



CURRENTS OF THE ATLANTIC 



77 



an equal value in the reciprocal exchange of seed-drift between the 
tropical regions on the opposite sides of the Atlantic. When we come 
to balance the account respecting the interchange of seed-drift 
between the Old and the New World, we learn that in the " give- 
and-take " process the gift from the New to the Old World would be 
slight. All the seeds borne to Europe in the Gulf Stream from the 
West Indian region would find uncongenial climatic conditions that 
would deprive the gift of any value. But better prospects would 
await those that chanced to be diverted south, either in the vicinity 
of the Azores, or further east in approaching European waters, 
where they would come within the influence of the Portuguese or 
North African Current. In both events they might possibly be 
stranded on the coasts of tropical Africa to the north of the Cape 
Verde Islands; but, as indicated by the bottle-drift, the chances 
are that they would not be stranded at all, but would be carried 
back to the West Indies in the stream of the North Equatorial 
Current. 

It is also highly probable that seed-drift from the Atlantic shores 
of North America, from Cape Hatteras northward, might be at times 
transported to the shores of Europe in the Gulf Stream drift, as is 
indicated in the tabulated results for bottle-drift before given. 
Such dispersal would be effective for the seeds of a few coast plants 
of temperate latitudes; but the seed-drift derived by currents from 
such regions is always small in amount and frequently ineffective 
for purposes of reproducing the plant. In my book on Plant Dispersal 
(pp. 429, 434, 438) it is shown that dispersal by currents is mainly 
restricted to warm latitudes. Whilst in the tropics seed-drift is 
abundant on the beaches, in the cooler regions of the globe it is 
usually very scanty and often masked by other vegetable debris. 

Another possible way by which the New World might occasionally 
present seed-drift to the Old World is afforded by the already 
mentioned westward extension of the Guinea Current at certain 
seasons of the year so as to constitute a counter equatorial current 
(see Note 19 of the Appendix). Acting as a " backwater " to the 
North and Main Equatorial Currents, it would be most effective in 
returning African seed-drift to Africa ; but at times, by extending 
nearer than usual to the New World, it might pick up a little drift 
from the north-east coasts of South America. Then again, as 
before suggested, it is probable that some of the drift gathered by 
the Brazil Current from the shores and estuaries of Brazil south of 
Cape St. Roque, as well as from the Rio de la Plata, might ultimately 
find its way by the South Atlantic Connecting Current into the South 
African Current and then into the Main Equatorial Current in the 
Gulf of Guinea. But whether it would be beached on the South 
African side seems unlikely, though there is an example of bottle- 
drift which might be instanced in this connection (p. 63). 

In the above discussion I have made the most of the possible and 
probable chances of the communication of seed-drift from the New 
to the Old World. The gifts at most would be unimportant and 
casual, and when effective of a belated kind. Not for a moment 
could a comparison be made with the large amount of effective 



78 PLANTS, SEEDS, AND CURRENTS 



seed-drift that must be rushed in a few months across the tropical 
Atlantic in the streams of the North and the Main Equatorial Currents. 
It is, as we have seen, only in the tropics that currents play an 
important part in plant distribution. For ages these two currents 
have been bearing their burdens westward direct from the African 
shores. Except for the occasional intervention of a counter-equatorial 
stream, as before described, there would be no direct return route 
from the American shores. 

Drift carried by Currents round Cape Horn, Cape Agulhas, 
and the North Cape. — It is noteworthy that drift has been known 
to double all the three great headlands which form the extremes of 
the continents of South America, Africa and Europe, towards the 
poles. Reference has already been made to this matter in different 
connections. Thus on p. 63 it is shown that bottles can be carried 
from off the coast of Natal round Cape Agulhas and across the 
South Atlantic to tropical Brazil, and from the Pacific side of Tierra 
del Fuego to the Falkland Islands. In neither case would the con- 
nection appear to be a frequent one; but the transference of seed- 
drift from the Indian Ocean to the South Atlantic would probably 
be the most effective. With regard to the doubling of the North 
Cape it is well known that West Indian seed-drift is carried by the 
Gulf Stream to the vicinity of this headland, and in Chapter II. it 
is pointed out that it may even double this promontory and reach 
the shores of the White Sea. I have no example of this having been 
accomplished by bottle-drift ; but that bottles can reach the vicinity 
of this cape from the other side of the Atlantic is shown in the U.S. 
Pilot Chart for December 1908, in the case of one dropped overboard 
off Cape Hatteras. 

Summary 

1. As indicative of the track followed by the drifting seed and of 
the time occupied in the traverse of the Atlantic the behaviour of 
the drifting bottle affords very important data (p. 46). 

2. After dealing with the sources of the materials employed, the 
value of bottle-drift for the study of the dispersal of seeds by currents 
is discussed. The small proportion of recoveries is pointed out 
(p. 48), and it is shown that the difficulties connected with the 
delays in the recovery are not so formidable as they at first seem 
(p. 49). The water-logged derelict from off Cape Hatteras, the 
baulk of mahogany from West Indian islands, the living turtle from 
the warm latitudes of the New World, the floating bottle containing 
the record of its start in Cuban waters or in Florida seas, the buoyant 
seed that could have grown only in the West Indies or on the tropical 
mainland of America, all tell the same story when they are stranded 
on our European beaches (p. 48). 

3. The treatment of the subject is divided into two parts: in the 
first place, the tracks followed ; in the second place, the time occupied 
by the drifting bottle; and in order to give method to the inquiry 
the accomplishment of the circuit of the North Atlantic is first 
dealt with. It is remarked that the circulatory movements of the 
currents in this ocean are equally well illustrated, whether the 



CURRENTS OF THE ATLANTIC 79 



circuit is performed by one bottle or piecemeal by a number of 
bottles (p. 51). 

4. The traverse from the West Indies and from the south-east 
coasts of North America to the shores of Europe in the Gulf Stream 
drift is then considered. The fan-shaped distribution of bottle- 
drift from the New World is then remarked, since it may be stranded 
anywhere on the east side of the North Atlantic between the North 
Cape of Norway and the coast of Morocco, reaching even the Canary 
Islands. From the results of experiments covering a long period of 
years it is inferred that drift may reach any given locality on the 
European coasts from all latitudes on the American side of the North 
Atlantic between the tropics and the sub-Arctic regions. Thus, 
bottle-drift is stranded on the Irish coasts from all latitudes between 
the Caribbean Sea and Davis Strait. The results of the extensive 
researches conducted with specially devised floats by the Prince of 
Monaco in the north-east Atlantic are here utilised (pp. 49-56). 

5. Having shown that bottles are carried across the North Atlantic 
to Europe from the West Indies in the Gulf Stream drift, the requisite 
data are adduced to demonstrate that they can be returned from 
European waters to the New World in the tropical latitudes of the 
same ocean by the North Equatorial Current. The facts indicate 
that from any locality in the Eastern Atlantic between the vicinity 
of the Irish coast and that of the Cape Verde Group bottles can be 
transported to any part of the West Indian region north of Barbados. 
A few of them finally reach the east coast of Florida after traversing 
the Lesser Antilles and crossing the Caribbean Sea and the Gulf of 
Mexico. This track must have been followed by a bottle that, after 
being cast over to the westward of the Cape Verde Islands, was 
recovered thirty-four months later on the Irish coast (pp. 56-59). 

6. After a short reference to the Guinea Current (p. 59), the 
next point of importance touched upon is the passage of bottles 
across the tropical Atlantic in the Main Equatorial Current from the 
Gulf of Guinea to the coast of Brazil. Guided by the bottle-drift 
data, the writer adopts the view that the two equatorial currents 
that approach the Brazilian coast north and south of Cape St. Roque 
are distinct in their origin, their course, and their destination; and 
he distinguishes them by the names, frequently used by other writers, 
of the Main and the South Equatorial Currents (pp. 60). 

7. It is shown that whilst the mass of the bottle-drift of the North 
Equatorial Current strikes the West Indian region north of Barbados, 
most of that of the Main Equatorial Current enters the region in 
the Trinidad waters to the south of that island. Of a hundred bottles 
thrown into the last-named current between North Brazil and St. 
Paul's Rocks nearly forty would be carried swiftly into the Caribbean 
Sea, to be distributed in most cases around its shores ; but sixteen of 
them would pass through the Straits of Yucatan into the Gulf of 
Mexico, and of these five would reach the Florida seas. Only a few 
of them would take the shorter route by the subsidiary Antillean 
Stream that flows east of the Lesser Antilles to the Bahamas 
(pp. 60-62). 

8. The indications of bottle-drift are then used to elucidate the 



80 PLANTS, SEEDS, AND CURRENTS 



part that would be taken by the South Equatorial Current and its 
southward extension, the Brazilian Current, in the distribution of 
seed-drift in the South Atlantic; and the same data are employed 
to illustrate the current-connections of this ocean with the Indian 
and Pacific Oceans. It is shown that bottle-drift can pass from 
the Indian Ocean into the South Atlantic round the Cape and may 
even reach Brazil, and that it can pass into the same ocean from the 
South Pacific round Cape Horn (pp. 62-63). 

9. The drifting rate of bottles in crossing the Atlantic is then 
treated; and after showing how the disturbing elements connected 
with the delay in their recovery may be largely eliminated, a table 
of general results is given (p. 66). It is inferred that the average 
time occupied in the passage from the West Indian region to Europe 
would be about fourteen months at a daily rate of about nine miles, 
and it is remarked that the average speed during different stages 
of the traverse is not much less. The fact that much slower rates 
are indicated by one of the series of the Prince of Monaco's observa- 
tions in the North-east Atlantic is explained (p. 68). The return 
passage from European waters to the West Indies usually covers a 
period of sixteen to seventeen months. But the rate varies in 
different parts of the traverse. In the passage south to the vicinity 
of the Cape Verde Islands it would be only four or five miles a day ; 
whilst in the trans-oceanic passage in the North Equatorial Current 
it would be nearly thirteen miles (p. 68). 

10. A much greater velocity is attained by bottle-drift in the 
swift stream of the Main Equatorial Current — namely, an average 
daily speed of thirty miles from the Gulf of Guinea to Brazil 
and of forty miles from off the Amazon estuary to Trinidad. About 
twelve weeks would generally be occupied in the trans-oceanic 
passage from the Gulf of Guinea to Brazil (p. 70). The data furnished 
by bottle-drift indicate that Amazon drift, crossing the Caribbean 
Sea and the Gulf of Mexico and following the Gulf Stream route, 
would arrive in European waters in about twenty months (p. 70). 
The average rate of bottle-drift in the Brazil Current does not exceed 
ten miles a day (p. 71). It is concluded that the complete circuit 
of the North Atlantic (from the Florida seas by the route of the 
Gulf Stream, the North Equatorial Current, the Caribbean Sea, and 
the Gulf of Mexico) would be accomplished in an average period of 
just three years (p. 72). The difficulties in demonstrating the 
completion of the circuit by the same bottle are very great. But 
it has been almost accomplished by derelicts. The nearest approach 
to a complete record is that of the bottle which was picked up on 
the west coast of Ireland thirty-four months after it had been cast 
into the sea to the westward of the Cape Verde Group (p. 72). 

11. Although the indications of the bottle-drift data open up 
great possibilities for the distribution of seed-drift in the North and 
South Atlantic, each ocean possessing its own independent circulatory 
system of currents, it must often happen that the transport of floating 
seeds from tropical to temperate latitudes, and vice versa, has no 
effective value. Whilst the North Equatorial Current brings to the 
West Indies the sweepings of the Atlantic seaboard of North America, 



CURRENTS OF THE ATLANTIC 



81 



of Southern Europe, and of North-west Africa, the Main Equatorial 
carries to the same region the sweepings of both sides of the South 
Atlantic. The burden borne westward by the current just named 
is, indeed, a motley one. Some of the greatest rivers in the world, 
the rivers of two continents, contribute to its freight, the Niger, 
the Congo, the Plate, the Amazon, and the Orinoco. Great im- 
portance is attached to the fact that the drift of the North and 
Main Equatorial Currents mingles in the Caribbean Sea (pp. 73-74). 

12. Attention is drawn to the interest that attaches itself to the 
island of Trinidad from the standpoint of the dispersal of plants by 
currents. It is the great centre of connection between the Old and 
the New World and between the South American mainland and the 
West Indian islands (p. 74). 

13. The probability that Amazon seed-drift reaches the shores of 
Europe opens up the possibility of West African seed-drift from the 
Congo and the Niger arriving on these coasts by the same circuitous 
route — namely, through the West Indies and in the Gulf Stream drift. 
This track seems to have been pursued by a bottle which was found 
afloat off the coast of Guernsey, after being dropped overboard near 
the island of Ascension. Sabine's observation on the transport of 
casks of palm oil from the Gulf of Guinea to Hammerfest bears on 
this point (pp. 75-76). 

14. When we come to balance the account respecting the inter- 
change of seed-drift between the Old and the New World, we learn 
that in the give-and-take process the gifts from the New to the Old 
World would be slight. As a rule they would be unimportant, 
ineffective,- and casual, and even when effective of a belated kind. 
Not for a moment could a comparison be made with the large amount 
of effective seed-drift that must be rushed in a few months across 
the tropical Atlantic in the streams of the North and Main Equatorial 
Currents (p. 76). 

15. In conclusion, it is shown that even the North Cape, Cape 
Agulhas, and Cape Horn form no insuperable barriers for the passage 
of seed-drift (p. 78). 

WORKS QUOTED IN CONNECTION WITH BOTTLE-DRIFT 
Becher, A. B., in Nautical Magazine for 1843 and 1852. 

Berghaus, H., Allgemeinen Lander und Volkerkunde, i., 1837, and Physikalischen 
Atlas (Abth. Hydrogr.). 

Daussy, Sur les observations de courants faites au moyen de bouteilles jetees a la 
mer, Comptes Bendus, 1839, viii., 81. 

Kohl, J. G., Geschichte des Golfstroms und seiner Erforschung : Bremen, 1868. 

Monaco, Prince Albert of, Sur le Gulf Stream: Paris, 1886 (Gauthier-Villars) ; 
different papers in Comptes Bendus, 1885-92, the final summary and tabulation 
of results in tome 114, 1892. 

Neumayer, G., Petermann's Geographischen Mittheilungen, 1868. 

Page, J., The U.S. Hydrographic Office, National Geographic Magazine, xii., 337 : 

New York, 1901. 
Purdy, J., in Columbian Navigator, iii., 31, 1839. 



82 PLANTS, SEEDS, AND CURRENTS 



Rennell, J., An Investigation of the Currents of the Atlantic Ocean : London, 1832. 
Russell, H. C, Journ. Boy. Soe. N.8. Wales, 1894, 1896. 

Schott, G., Die Flaschenposten der Deutschen Seewarte, Archiv der Deutschen 
Seewarte, xx., 1897, Hamburg. 

U.S. Hydrographic Office, Washington, Bottle-drift charts on the backs of the 
North Atlantic Pilot Charts, October to May, 1900-8. 

Wood-Jones, F., Coral and Atolls, London, 1910, pp. 294-5, contains results of 
bottle-drift experiments in the Indian Ocean. 



CHAPTER IV 



THE SIMILARITY BETWEEN THE WEST INDIAN AND WEST AFRICAN 
LITTORAL FLORAS AS EXPLAINED BY CURRENTS 

The similarity between the West Indian and West African littoral 
floras has long occupied the attention of botanists, and particularly 
of the late Prof. Schimper. It is a subject that is intimately bound 
up with the question of the dispersal of plants by currents ; but a 
little clearing of the ground is first requisite in order to appreciate 
its true significance. 

The Discontinuity of Tropical Genera possessing Littoral 
Species. — A very noticeable and not infrequent feature in connec- 
tion with the littoral trees of the tropics of the Old and New World 
is the discontinuous distribution of the genera as far as all the non- 
littoral species are concerned. Though the littoral species is in each 
case widely distributed in both the western and eastern hemispheres, 
the genus is also represented by peculiar species in both worlds, and 
in such a manner that we are often left in doubt whether the shore 
species has its home in the east or in the west. In all such cases 
it is only the littoral species spread by the currents that connects 
the two hemispheres. Otherwise the discontinuity would be com- 
plete. As examples we may give Chrysobalanus, Entada, Thespesia, 
and Ximenia. But this discontinuous distribution raises many 
difficulties, whilst it removes others. 

Thus, as far as the range of the genus is concerned, the New World 
has as much claim as the Old World to be considered the home of 
Thespesia populnea, since the six other known species are shared 
equally by the two hemispheres. But other genera than those 
named above present new points of difficulty. Thus Symphonia 
is a genus of twelve or thirteen species, of which nearly all are con- 
fined to Madagascar and two occur in Africa. A single estuarine 
species, S. globulifera, which connects West Africa with the New World 
has apparently no means of crossing the Atlantic. Then we have 
Terminalia with a large number of species spread over the tropics 
of both hemispheres ; but truly littoral species occur only in the Old 
World, and there is no species connecting the two hemispheres. 
Then there is Crudya with nearly all its dozen species American. 

This discontinuity presents no great difficulties when it affects 
genera found in the tropics of both hemispheres which are only 
connected together by littoral species that are known to be dispersed 

83 



84 PLANTS, SEEDS, AND CURRENTS 



by currents ; and the same may be said of those genera without littoral 
species where there is no connection between America and the Old 
World, as in the case of Mammea with six known species, of which 
three are restricted to tropical America and three are known only 
from Madagascar. Here we are concerned with the original dis- 
tribution of the genera in the tropical zone, and the presence or 
absence of any link between America and the eastern hemisphere 
seems to be a matter of fitness for dispersal by currents. One can 
also understand cases like Terminalia, where the absence of any 
species linking the two worlds may be concerned with the circum- 
stance that the littoral species capable of being spread by the currents 
are not found on the West African coast ; but the behaviour of the 
genera, Symphonia and Crudya, is not easy to comprehend, since 
there we have one genus almost entirely of the Old World with only 
a single outpost in America, and another almost entirely American 
with a distant representative in the Philippine Islands. 

The important lesson to be learned from the discontinuity of 
genera in tropical latitudes is that we can only appeal to the currents 
in the case of the littoral species, the original distribution of the genus 
around the tropical zone being quite another matter. Facts of this 
kind go far to limit the sphere of influence of the oceanic current in 
determining plant distribution. Currents have done little to con- 
fuse the great issues raised by the genera. Whilst they have often 
effected the mingling of littoral floras of continents, the main facts 
of distribution are largely undisturbed. With these introductory 
remarks we will now proceed to discuss the similarity of the West 
Indian and West African littoral floras, and in so doing we will take 
up again the story of the beach-drift. 

An Appeal to the Oceanic Currents. — Perhaps the most im- 
portant question raised by the study of West Indian beach-drift is 
suggested by the fact that more than half of the plants that con- 
tribute to it (beach plants, mangroves and their associates, estuarine 
plants, and inland plants that grow at times at the riverside) occur 
outside the New World. Almost all of the Old World plants here 
concerned have been recorded from West Africa; and there can be 
little doubt that the few exceptions, most of which have been 
observed on the east side of the continent, will disappear with future 
inquiry. 

This fact at once leads one to investigate the relation between the 
occurrence of these West Indian plants in West Africa and their 
suitability for dispersal by oceanic currents. To each of these 
plants, as well as to those that are restricted entirely to the New 
World, the question has been put, whether or not its fruit or seed, 
as the case may be, could be transported without loss of the germina- 
tive power in the Main Equatorial Current from West Africa to Brazil. 
This, as is shown in Chapter III., is the shortest available route 
between the two Worlds for the transference by currents of floating 
fruits and seeds. It requires a capacity on the part of the fruit 
or seed of floating unharmed from two to three months in sea- 
water, and of being able to withstand the ordinary buffeting of the 
waves. 



WEST INDIAN AND WEST AFRICAN FLORAS 85 



The question is put and answered in the table given on p. 86, in the 
columns of which are embodied the results of the author's observa- 
tions and experiments, as well as literary research, extending over 
a period of more than thirty years, and carried out in many localities 
both in the Old and the New World. There are not more than three 
or four of the fifty-three plants named in the table with which he is 
not familiar in their homes, and in all but one he is acquainted 
with their fruits and seeds, and has investigated their capacity for 
dispersal by currents. 

With the exception of the group of small-seeded plants, which, 
since they raise other considerations besides those concerned with 
currents, are not here dealt with and are discussed in Note 21 of the 
Appendix, we have represented in this table the principal littoral, 
estuarine, and riverside plants of the West Indies. All offer them- 
selves for the application of the test. 



Explanatory Notes of the Following Table 

(a) The results given in the buoyancy column refer only to the 
period during which the seed retains its germinative capacity 
whilst afloat. Flotation may continue long after the death of the 
seed. 

(b) The plants marked ? in the West African column occur in 
all probability in West Africa, though in the works of reference at 
my disposal that region is not specially particularised, and they 
are as a rule merely described as found on all tropical coasts. It 
may be assumed that plants like Suriana maritima and Colubrina 
asiatica, which are found in the West Indies and in East Africa, 
also occur in West Africa, though in the case of the Old World 
they are usually only mentioned as existing on all tropical 
coasts. 

(c) The occurrence of the plants on the Pacific coasts of tropical 
America is indicated in the table as far as the data at my disposal 
allow. The distribution is often stated in such a general way in 
works of reference that it is not possible to learn with certainty 
whether or not the plant concerned exists on the Pacific as well as 
on the West Indian side of the New World. This is unfortunate, 
since the question is one of considerable interest, especially as regards 
true littoral plants. It is, however, probable in most of the cases 
where no indication is given in the table that the plant also grows 
on the Pacific coast. 

(d) The list of beach plants restricted to the New World could be 
considerably extended if buoyancy data were available; but it is 
very doubtful whether any of them would possess seeds or fruits 
with great floating powers. One may mention Ernodea litoralis, 
Rhachicallis rupestris, and Phyllanthus falcatus. Then there are 
plants of Amarantaceous genera, such as Alternanthera and Litho- 
phila, as well as different sedges, such as Cyperus brunneus, etc., 
and grasses, such as Uniola paniculata, Cenchrus tribuloides, etc. 



86 PLANTS, SEEDS, AND CURRENTS 



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88 PLANTS, SEEDS, AND CURRENTS 



Tabulated Results of the Preceding Table 





Total 


Distribution 


Fitted for dis- 
persal by the 

Main Equato- 
rial Current 


Eemarks 






New 
World 
only 


Old and 

New 
Worlds 


New 
World 
only 


Old and 

New 
Worlds 




Mangroves and associates 
Estuarine plants . 


6 
6 


5 


6 
1 


1 


5 


The incapacity of 
Drepanocarpus is only 


Plants of inland 
wooded districts grow- 
ing at times at the river - 


12 


6 


6 


1 


5 




Beach plants ranging 
through tropical and 
subtropical regions . 


16 




16 




16 




Beach plants confined 
to the New World and 
West Africa .... 


3 




3 




2 




Beach plants confined 
to the New World . 


10 


10 




3 




The number could be 
considerably extended, 
if buoyancy data were 
available. [See previous 
Explanatory Note (d).] 


1 53 


21 


32 


5 


28 





Summary of the above tabulated results. 

Of the 53 plants, 32, or 60 per cent., occur in both Worlds, and 33, or 62 per 
cent., respond to the current test in their fitness for transport by the Main 
Equatorial Current. 

Of the 32 plants occurring in both Worlds, 28, or 88 per cent., respond to this 
test; but only 24 per cent. (5 out of 21) do so of those confined to the New World, 
a proportion that doubtless would be considerably lessened if more buoyancy data 
were available. 

The plants that are exceptions to the rules. 

The three plants that occur on opposite sides of the tropical Atlantic but could 
not be floated across the ocean are Andira inermis, Ecastaphyllum brownei, and 
Symphonia globulifera. Possibly a fourth would be Drepanocarpus lunatus. 

The five that are restricted to the New World, yet are able to cross the Atlantic 
between West Africa and Brazil, are Hippomane mancinella, Morinda royoc, 
Sacoglottis amazonica, Sapindus saponaria, and Tournefortia gnaphalodes. 

The Test of Capacity for Dispersal by Currents. — There 
are presented in the above table fifty-three West Indian plants of 
which thirty-two, or 60 per cent., are found outside the New World, 
and in nearly all cases on the shores and in the estuaries of tropical 
West Africa. Of these Old World plants all but four, or 88 per cent., 
give an affirmative reply when interrogated as to the fitness of their 



WEST INDIAN AND WEST AFRICAN FLORAS 89 



fruits and seeds for transport across the Atlantic from the Gulf of 
Guinea to South America in the Main Equatorial Current. We 
are not concerned just at present with the indications that this test 
might yield of a West African origin of many of the West Indian 
littoral and estuarine plants. For the moment we will simply 
regard this as a proof of capacity for accomplishing the traverse of 
the tropical Atlantic. When we regard the twenty-one plants that 
are restricted to the New World we find that only five, or 24 per 
cent., respond to the test. It should here be repeated that the 
list of plants confined to the New World could be considerably 
augmented, and that the effect would be to markedly diminish the 
proportion of those that respond to the test. With reference to the 
five plants that are restricted to the New World, notwithstanding 
their capacity for crossing the tropical Atlantic, we shall subse- 
quently see that in negativing any reciprocal interchange of littoral, 
estuarine and riverside plants between the Old and the New World 
they afford a clue to the origin of most of the West Indian plants 
of these stations that have been found in the Old World. 

(A) Its Application to the Plants in the Mass. — The issue 
may thus be stated. Whilst nearly 90 per cent, of the plants that 
are common to the West Indies and West Africa possess seeds or 
fruits that could be transported by the currents from the Gulf of 
Guinea to Brazil, less than one-fourth of those restricted to the 
West Indian side possess the same capacity, but have not extended 
their range outside the New World. The matter thus resolves itself 
into a question of the opportunities offered by the Atlantic currents, 
concerning which it has already been brought out in Chapter III. 
that whilst the Main Equatorial Current offers a ready and rapid 
means of transport for fruits and seeds from West Africa to the 
New World, the opportunities of West Africa receiving West Indian 
seeds and fruits in a sound condition are small. Reference may here 
again be made to the fact that De Candolle in his work on Botanical 
Geography (pp. 763-4) places an equal value on the Gulf Stream 
and the Equatorial Currents of the Atlantic in the reciprocal exchange 
of drift between the opposite tropical regions. This is a serious 
error, since the long circuitous route by the Gulf Stream, which 
would involve a minimum passage of two years, would for all but a 
very few leguminous plants negative any chance of effective dis- 
persal. The Brazilian Current would not tap the West Indian region 
at all, and the return of any of its seed-drift to tropical Africa would 
involve a very lengthy passage and a somewhat complex series of 
current connections. The only chance would be that offered by 
the Equatorial Counter Current ; but it is shown that the occasions 
in which it would extend far enough to the west to tap the New 
World as a source of drift would be few, though not altogether 
negligible. 

(B) Its Application to the Plants according to their 
Station. — Having applied this test to the plants in the mass we will 
now apply it to them according to their station. 

(a) The Mangroves. — In the first place come the mangroves and 
their associates, all of which are West African as well as West Indian. 



90 PLANTS, SEEDS, AND CURRENTS 



The true mangroves comprise Rhizophora mangle, Avicennia nitida, 
and Laguncularia racernosa ; whilst their associates at the borders 
of the swamp include Anona palustris, Carapa guianensis, and 
Drepanocarpus lunatics. With all of them, except the last, con- 
cerning which the requisite data are lacking, it is possible that the 
Main Equatorial Current could have transported them from the African 
coast to the shores of Brazil and the Guianas, but it would be under 
varied conditions. Whilst Rhizophora would arrive in the form of 
floating seedlings, with Avicennia and Laguncularia the germinating 
fruits would be concerned. When pointing out in my book on 
Plant Dispersal the obvious risks to which the seedlings and germi- 
nating fruits would be exposed during a long ocean passage, I felt 
constrained to admit (p. 77) that their capacity for effective dispersal 
across an ocean must be postulated. 

At that time the position adopted was that America had supplied 
West Africa with its mangroves. This I regard now as untenable, 
and a later consideration of the current question, as discussed in 
Chapter III., has convinced me that an average period of only twelve 
weeks would be required for the transport of seed-drift from the Gulf 
of Guinea to Brazil, whilst under especially favourable circumstances 
this period might be reduced to two months. Though the seedlings 
and germinating fruits of the mangroves could scarcely withstand 
the wear and tear of an ocean passage of six months, it seems probable 
that they would survive a passage of half this duration. With 
regard to the floating seeds of plants like Anona palustris and Carapa 
guianensis, which are associated with the mangroves, it is likely 
that they could only accomplish an ocean traverse of from two to 
four months with sound kernels. For long passages of many months 
they would be quite unfitted as far as the preservation of their 
effective condition is concerned. 

(b) The Estuarine Plants. — Apart from the mangroves and their 
associates there are estuarine plants, such as Crudya spicata, Fevillea 
cordifolia, Grias cauliflora, Manicaria saccifera, Sacoglottis amazonica, 
and Symphonia globulifera, all of which contribute their seeds or 
fruits to the floating drift that is borne seaward and distributed 
by the currents. Whilst all the mangroves and their associates are 
also West African, five of the six plants just named are confined to 
the tropics of the New World. With the exception of Sacoglottis 
amazonica there is not one of them, however, that gives promise of 
being able to withstand without injury an immersion of months in 
the sea, and this oddly enough is not the Old World plant. The 
buoyancy of the seeds or fruits may be so great that as with Saco- 
glottis amazonica and Manicaria saccifera the fruits have been known 
to be stranded on the shores of Europe ; but the indications plainly 
show that they would not be in a germinable condition. Yet it is 
strange that the plant which is least fitted for oceanic dispersal, 
namely, Symphonia globulifera, is the only one of the six that has 
been found outside the New World, that is, in West Africa. This 
plant is one of the puzzles of distribution, and we shall see its riddle 
repeated in one or two other cases mentioned below. 

Whilst in Symphonia globulifera we have an estuarine tree growing 



WEST INDIAN AND WEST AFRICAN FLORAS 91 



on both sides of the tropical Atlantic that could not possibly, as far 
as its seeds or its fruits are concerned, have accomplished the ocean 
traverse, we have in Sacoglottis amazonica another estuarine tree, 
which, although it is restricted to the New World, presents in its 
buoyant fruits some capacity for reaching the Old World. In the 
first case other influences than those of currents have determined its 
distribution. In the second case the determining factors have been 
the arrangement of the currents and the insufficiently persistent 
vitality of the seeds. Whilst the fruits of Sacoglottis amazonica 
could perform the two years' traverse to the African coast by the 
Gulf Stream route in the North Atlantic, the seeds would probably 
lose their germinative power after six months. Though not im- 
possible, the direct route by the Counter Equatorial Current is 
largely negatived in this case by the extensive bottle-drift data given 
in Chapter III. 

(c) Inland Plants growing occasionally at the Riverside. — In con- 
nection with West Indian rivers there is another group of plants, 
the fruits of which often fall into the stream from the parent plants 
growing on the banks beyond the reach of the tide, and are then 
carried down to the sea to be distributed far and wide by the currents. 
The distinction, however, is a little artificial, since quite half of the 
plants would be found at times on the coast ; and there are some, like 
Entada scandens, which, though usually growing inland in the West 
Indies, are typically littoral in their station in the Pacific islands. 
This group can be subdivided into (a) those found in tropical West 
Africa, such as the leguminous climbers, Entada scandens, Mucuna 
urens, and Dioclea reflecca, and the trees, Andira inermis and Spondias 
lutea ; and (b) those confined to the New World, such as Mammea 
americana, Sapindus saponaria, Crescentia cujete, C. cucurbitina, and 
the palms Astrocaryum and Acrocomia. 

Here there is a certain relation between distribution and fitness 
for dispersal by currents. With the exception of those of Sapindus 
saponaria, none of the fruits or seeds of the purely New World plants 
could accomplish an ocean traverse of two or three months' duration 
without loss of the germinative capacity, though capable of floating 
for much longer periods in an ineffective state. But even Sapindus 
saponaria may not prove to be an exception, since there are indica- 
tions dealt with in the special treatment of the plant that it might 
be regarded as an Old World species. Of the five plants also at 
home in West Africa all but Andira inermis possess seeds or fruits 
that could perform in safety the ocean passage from West Africa 
to Brazil. In the case of the seeds of the leguminous climbers they 
could do very much more, since these seeds retain their germinative 
capacity after being carried in the Gulf Stream to the shores of 
Europe. Andira inermis presents the same difficulty as Symphonia 
globulifera. Though it occurs on both sides of the tropical Atlantic, 
it is not able to cross it. 

(d) Beach Plants. — We come now to the beach plants, those that 
border the beaches and thrive on the sandy tracts in the rear. They 
arrange themselves into three groups : the cosmopolitan plants 
extending in a general sense over the continental and insular coasts 



92 PLANTS, SEEDS, AND CURRENTS 



of the tropics and subtropics of both hemispheres, those confined to 
the New World and the west coast of Africa, and those entirely- 
restricted to the New World. 

The Cosmopolitan Beach Plants. — In the case of this group we 
are dealing with plants that have travelled in most instances prac- 
tically around the globe. They include five leguminous species, 
Canavalia obtusifolia, Guilandina bonduc, G. bonducella, Sophora 
tomentosa, and Vigna luteola ; two malvaceous species, Hibiscus 
tiliaceus and Thespesia populnea ; three convolvulaceous species, if 
we include Ipomoea carnosa with /. pes-capraz and /. tuba ; and six 
others belonging to as many different orders — namely, Cassytha 
filiformis, Colubrina asiatica, Dodoncea viscosa, Sc&vola plumieri, 
Suriana maritima, and Ximenia americana. There are a few of these 
plants that could scarcely be considered as universally distributed 
in warm latitudes, but the differences that separate them from the 
others are only in degree. Thus both Sc&vola plumieri and Vigna 
luteola occur on both coasts of the New World and on both coasts 
of Africa; but since the first extends to India and Ceylon and the 
second exists in Australia, it would be difficult to exclude them. 
In giving Ipomoea tuba a very wide distribution I have followed 
Urban, and the reasons in the case of /. carnosa are given in the 
reference named. 

Every one of these fifteen or sixteen widely spread beach plants 
has buoyant seeds or fruits (in most cases it is the seed that is con- 
cerned) which can float for a long time unharmed in the sea; and 
respecting some, such as the two species of Guilandina and Thespesia 
populnea, it is known that their seeds can float 'for a year in the 
sea without loss of the germinative capacity. A plant has, in fact, 
been raised from a Guilandina seed cast ashore on the coast of Ireland. 
But there is not a species in this group of beach plants that would 
not respond to the test involved in the transport of their seeds or 
fruits in a sound condition from West Africa to Brazil in the Main 
Equatorial Current, though in the case of Dodon&a viscosa the 
minimum limit of flotation-capacity is only just attained. 

The Beach Plants restricted to the New World and West Africa. — 
When the test above mentioned is applied to the small group of 
beach plants that beyond the New World are only known from the 
shores of West Africa, we find that two out of the three respond to 
it — namely, Chrysobalanus icaco and Conocarpus erectus. The third, 
Ecastaphyllum brownei, presents the same problem that was offered 
by Andira inermis and Symphonia globulifera amongst the riverside 
and estuarine plants. Here we have three plants that grow on the 
opposite sides of the tropical Atlantic with to all appearance no 
capacity for accomplishing the ocean passage. At first sight it 
would seem that the validity of the current hypothesis is here im- 
pugned; but in one case, at least, it is likely that quite other con- 
siderations arise. Thus Symphonia globulifera, an estuarine tree, 
belongs to a genus that is mainly confined to Madagascar, the excep- 
tions being two West African species, one of which, as in the present 
case, is found in the West Indies. It is obvious that the discon- 
tinuous distribution here indicated may not be connected with means 



WEST INDIAN AND WEST AFRICAN FLORAS 93 



of dispersal at all. A curious question is raised in the case of 
Conocarpus erectus, the small seed-like fruits of which possess con- 
siderable floating powers. It grows on the Pacific coasts of tropical 
America, and its absence from the Pacific islands is remarkable, 
since there seems to be no reason, as far as its capacity for dispersal 
by currents is concerned, why it should not have reached the eastern 
islands of the tropical Pacific. The same difficulty is presented by 
the Manchineel tree (Hippomane mancinella), a matter which is 
referred to below. When dealing in detail with Conocarpus erectus 
it will be pointed out that Schimper regarded it as a current-dispersed 
plant. On the whole it may be considered that the three beach 
plants of tropical America that are only known outside the New 
World from the shores of West Africa raise many difficulties. 

The Beach Plants confined to the New World. — On the other hand, 
when we come to the West Indian beach plants that have not been 
found outside the New World we learn that of the ten plants named 
in the table the majority do not respond to the test. Whilst most 
of them possess fruits or seeds that can only float for a few days or 
weeks, in three cases, those of Hippomane mancinella (the Manchineel 
tree), Tournefortia gnaphalodes, and Morinda royoc, the floating 
capacity covers several months and may extend to a year or more. 

To illustrate this point I will take the case of the Manchineel 
tree, the fruits of which are one of the most common constituents 
of beach-drift in the West Indian region ; and there can be no doubt, 
as shown on a later page, that they can float for many months in 
the sea with their seeds uninjured. It is a tree that has held its 
present area for ages. In the hammocks of the Florida everglades 
there have found a sanctuary many West Indian plants that flourished 
in the same locality when the hammock-lands represented an ancient 
system of keys or low islands that rose from the waters at the time 
that the Gulf Stream flowed across the present peninsula of Florida 
(Harshberger, p. 230). The Manchineel was one of them. For a 
long period currents have afforded considerable opportunities for 
the transference of littoral plants from West Africa to the New 
World, but very few for a transference from America to Africa. 
Yet it may be argued that since the Manchineel grows on the beaches 
of the Pacific coast of the New World its fruits could have reached 
the Old World across the Pacific. However, the complete traverse 
of the ocean would occupy a period of two or three years, a subject 
discussed in Chapter XIII. Yet only about half that time would be 
required for its fruits to reach the Paumotuan, Tahitian, and Mar- 
quesan groups in mid-Pacific, and it is difficult to understand why 
the tree has not been recorded from the beaches of the Pacific islands. 

It is still more difficult to understand, in the case of the tropical 
Atlantic, why, if the Counter Equatorial Current is an effective 
agency in seed dispersal, beach plants like the Manchineel, Tourne- 
fortia gnaphalodes, and Morinda royoc have not reached West Africa 
from the New World, and we may say the same of Sacoglottis amazonica 
among the estuarine plants. The time required for this traverse 
would be about double that needed for the traverse in the Main 
Equatorial Current in the opposite direction, and all these American 



94 



PLANTS, SEEDS, AND CURRENTS 



plants would be able to withstand the six months' passage, as far 
as the buoyancy and soundness of their seeds and fruits are con- 
cerned. The implication is that the Counter Equatorial Current is 
ineffective for this purpose, and if it has not enabled these four 
plants to cross the Atlantic and pass the barrier that divides them 
from West Africa, it could have offered no opportunity to other 
American beach plants, such as Coccoloba uvifera, etc., that are far 
less suited for dispersal by currents. 

Summary 

1. Before dealing with the similarity between the West Indian 
and West African littoral floras, a subject intimately bound up with 
the dispersal of plants by currents, the ground is cleared by a brief 
discussion of the discontinuity of tropical genera, with the object 
of showing that whilst we can only appeal to the currents in the 
case of the littoral species, the distribution of the genus around the 
tropics often raises other issues (pp. 83-84). 

2. The important conclusions arrived at in the previous chapter 
that the Main Equatorial Current offers a ready and rapid means 
of transport for fruits and seeds from tropical West Africa to the 
New World, and that the opportunity of their reaching West Africa 
in a sound condition from the tropics of the New World is very 
slight, are here utilised. Except in the case of the small-seeded 
beach plants, where other questions than those of dispersal by 
currents are concerned, the test of fitness for transport in the Main 
Equatorial Current from West Africa to Brazil is now applied to 
the littoral, estuarine and riverside plants of the West Indies. In 
answer to the question whether or not they respond to the test, 
the following results have been obtained (pp. 84-88). 

3. Taking the plants in the mass, nearly 90 per cent, of those found 
in the tropics of both the Old and the New World and only 24 per 
cent, of those confined to the New World possess seeds or fruits that 
would be able to undergo this trial (pp. 89). 

4. But this testimony in favour of the currents is not equally 
provided by the plants when regarded from their different stations. 
Whilst the mangroves with their usual associates and the numerous 
cosmopolitan beach plants, all of them typical of both sides of the 
Atlantic, respond almost without exception to the test, the majority 
of the beach plants restricted to the New World (seven out of ten) 
do not comply with it. Similar direct and indirect testimony on 
behalf of the currents is supplied by the plants that grow often at 
the riverside, especially in the wooded districts above the estuary. 
Here the purely New World types are as a rule quite unfitted for 
effective oceanic dispersal, while those found on both the American 
and the African sides are in most cases adapted for it (pp. 89-94). 

5. On the other hand, the evidence of the six estuarine plants points 
in the opposite direction, since the only one that occurs outside the 
New World is quite unsuited for the ocean traverse, while one of 
those that are peculiarly American is well fitted for it (pp. 90-91). 

6. It will be therefore observed that although on the whole the 



WEST INDIAN AND WEST AFRICAN FLORAS 95 



general verdict strongly favours the current hypothesis, there are 
some important exceptions. With the mangroves and their asso- 
ciated plants, as well as with the cosmopolitan beach plants, the 
vote is practically unanimous. With the American beach plants 
and with the riverside plants it is a majority vote, whilst with the 
estuarine plants the evidence is conflicting and at times apparently 
hostile (pp. 89-94). 

7. Yet the ultimate tendency of the qualifying cases may not 
necessarily be hostile. The implication of the behaviour of such 
peculiarly American plants as Sapindus saponaria, Hippomane 
mancinella, Morinda royoc, Saco glottis amazonica, and Tournefortia 
gnaphalodes, which possess fruits or seeds well suited for the direct 
ocean traverse, may be that the currents have given them no oppor- 
tunity of extending their range eastward beyond the New World, 
since, as we have seen, the facilities offered by the currents to West 
African littoral plants of reaching America are very much greater 
than the opportunities supplied to American tropical shore plants of 
extending their range to West Africa. But here another difficulty 
arises in the case of certain of the littoral plants which border 
the beaches on the Pacific coasts of tropical America. It is not 
easy to understand why Conocarpus erectus and Hippomane mancinella 
that are evidently well fitted for oceanic dispersal, have not reached 
some of the easternmost groups of the tropical Pacific through the 
agency of the equatorial currents (pp. 93, 94). 

8. In the case of plants like Andira inermis, Ecastaphyllum brownei, 
and Symphonia globulifera, which, although existing on both sides 
of the tropical Atlantic, have neither fruits nor seeds that could 
cross the ocean in a sound condition even by the most direct route, 
it is probable that other considerations arise which are concerned 
with the original distribution of the genus in both worlds (pp. 92, etc.). 

9. Probably the most significant general conclusion in this sum- 
mary is given in the third paragraph ; and it is in this connection 
essential to remember that if buoyancy data had been available for 
several plants not included in the list, the proportion responding to 
the test among littoral plants confined to the New World would in 
all likelihood have been as low as 15 per cent. 



CHAPTER V 



RHIZOPHORA MANGLE AND THE PLANTS OF THE GREAT MORASS OF 
THE BLACK RIVER DISTRICT IN JAMAICA 

This species of mangrove is so universally spread in the West 
Indies that there will be no necessity to name the various localities 
in which I found it. My numerous observations on the plant in 
Fiji and Ecuador are described at length in my book on Plant 
Dispersal. Here I will merely add my West Indian observations, 
contrasting them as occasion requires with the results previously 
obtained. 

On the Period required for the Growth of Rhizophora 
Seedlings on the Tree. — Reference will first be made to the length 
of time that elapses in different species of Rhizophora between 
fertilisation and the fall of the seedling from the tree. In the work 
above named (pp. 457, 466) it is stated that whilst Jacquin in the 
West Indies placed this period at eleven to twelve months for 
Rh. mangle, my own observations in Fiji for the same species gave a 
result of eight to nine months. The considerable variation in the 
length that the seedling attains on the tree will explain this differ- 
ence. For Rh. mucronata in Fiji, I placed the period at about ten 
months. These results may now be supplemented by those given 
by Kerner in his Natural History of Plants (Oliver's translation, 
I., 603) for another Asiatic species, Rh. conjugata. Apparently 
quoting Ransonnet, he writes that the hypocotyl reaches its full 
length of 30 to 50 cm. in from seven to nine months. With these 
results we have now the requisite data for all the three species that 
are usually recognised as constituting the genus Rhizophora, and the 
view expressed in my work that a period of nine or ten months is 
typical of the genus thus holds good. 

On the Ability of Rhizophora Seedlings to withstand 
Drying. — It is remarked in my previous work (p. 461) that stranded 
Rhizophora seedlings would be able to withstand drying for months, 
provided that they were protected by a covering of vegetable drift 
or of sand; and an experiment in Fiji is described in which two 
stranded seedlings, kept dry in my room for nine weeks, developed 
leaves and roots when afterwards planted in the mud of a mangrove 
swamp. However, the results of a more recent experiment on 
West Indian seedlings, which are given below, indicate that under 
favourable conditions seedlings can retain their vitality in the dry 
state for five months ; and one cannot doubt that, if the experiment 
had been conducted under more natural conditions in the tropics, 

96 



RHIZOPHORA MANGLE 



97 



the results would have been still more marked. It is well known 
that these seedlings readily strike when stranded on a mud-flat, and 
my observations show that they do the same on a sandy beach, 
though often abortively. The point here investigated is their 
capacity of postponing this process. 

On the Vitality of Seedlings of Bhizofhoba mangle which had been kept 
Dey foe Five Months afteb being gathebed fbom the Tbee 

(They varied in length from 6-6 to 12-3 inches (168-312 mm.), and were detached 
from the fruit-case. The experiment was carried out during June and July in 
England in a greenhouse, and, therefore, under warm conditions. The measurements 
were made from the base of the plumule to the tip of the hypocotyl.) 



Dried Seedlings 


Increase in Weight 


Increase in Length 


Five seedlings kept afloat between 
4 and 5 weeks in fresh water. 
Original length in dry state, 6-6 to 
8-9 inches. 


17 to 25 per cent. 


0-2-0-3 inch(5-7£ mm.) 


Three seedlings kept afloat be- 
tween 4 and 5 weeks in sea-water. 
Original length in dry state, 6-6 to 
12-3 inches. 


10 to 20 per cent. 


0-2 inch (5 mm.) 


Two seedlings kept afloat between 
4 and 5 weeks in sea-water. Original 
lengths in dry state, (A) 8-9 inches. 
(B) 12 inches. 


(A) 54 per cent. 

(B) 48 per cent. 


(A) 0-6 inch (15 mm.) 
(B) 1-0 inch (25-4 mm.) 

1 



All the seedlings were much shrunken, wrinkled, and blackish 
along their whole length, with the exception of the lower end, which, 
for a distance of from one to two inches from the tip of the hypocotyl, 
retained a bright green hue and was less withered. Evidently the 
seedlings in fresh-water regained only a part of the water that they 
held in the living state, and the small increase in length of from 
5 to 7 mm. was in the main the result of the swelling process. 
Three of them placed in sea- water behaved like those in fresh- water, 
and here it is also apparent that little or no actual growth occurred. 
However, two of those in sea- water behaved very differently. They 
absorbed, relatively speaking, twice or three times as much water, 
and increased their length in the one case by 15 mm. and in 
the other by 25 mm. The growth was hypocotylar, since the 
measurements were made from the base of the plumule to the tip 
of the hypocotyl. Rootlets were not developed. No effort was 
made to unfold the plumular leaves, nor was there any marked 
increase in length of the plumule, such as could be attributed to 
growth. 

This experiment is interesting from the fact that it supplied its 
own " control " in the case of the three seedlings that behaved in 
sea-water like those in fresh-water and showed no active growth. 
One of the implications is that Rhizophora seedlings, after falling 

H 



98 



PLANTS, SEEDS, AND CURRENTS 



into the sea from the tree, may proceed with the hypocotylar growth 
whilst afloat, though probably rootlets would not be produced. This 
growth would naturally be more marked than in the case of the 
dried seedlings experimented on. We would expect that in ordinary 
circumstances the floating Rhizophora seedling, if prematurely 
detached, would add some inches to its length. 

However, it does not appear that growth is long continued in the 
case of fruits, detached in the early stage of germination, which fall 
into the sea. Germinating fruits, with the hypocotyl protruding 
half an inch or less, may be at times broken off from the tree through 
the agencies of storms and animals. Such fruits sink at once, and 
it was ascertained by experiment in fresh-water that although the 
germinating process was continued for the first five or six days 
under water, the protruding portion adding about 3 mm. to its 
length, the hypocotylar growth was arrested after a week. Fruits 
of full size, but displaying no protrusion of the radicle, made no 
attempt to do so whilst lying for a fortnight in fresh-water. The 
curious appearance of a Rhizophora fruit in the early germinating 
stage, which had been broken off and was lying in the ooze under 
the tree, led me to plant a number of such fruits in the mangrove 
mud with the hypocotyl in the air, thus reversing the normal position. 
Under these unusual conditions fruits with the seedling protruding 
between 12 and 18 mm. added from 2 to 3 mm. to the length of the 
hypocotyl during the course of three weeks and remained in most 
cases quite healthy. 

The Proportion of Germinating Fruits of Rhizophora 

MANGLE THAT DISPLAY MORE THAN ONE SEEDLING. In my book 

on Plant Dispersal (pp. 449, 466) I deal with the fact that whilst, as 
a rule, only one of the four ovules in a fruit of Rhizophora becomes a 
seed, occasionally two seeds and even three seeds are developed. 
Out of more than 2000 germinating fruits of Rh. mangle examined 
in Fiji, mainly in the Rewa delta, about 1 per cent, displayed more 
than one hypocotyl. In these cases there were usually two and very 
rarely three hypocotyls, the rate of frequency of fruits displaying 
three seedlings not exceeding 1 per 1000. These results apply to 
the total number of fruits observed, but there were localities in 
which the proportion of fruits bearing more than one seedling 
amounted to between 2 and 3 per cent. 

These observations were extended in the West Indies in the case 
of the same species, about 1000 germinating fruits being examined, 
500 of them in the delta of the Black River, Jamaica, and the rest 
at St. George's, Grenada. In the locality first named just 2 per 
cent, displayed two seedlings, no fruit with three hypocotyls being 
noticed. But considerable variation was exhibited by different 
trees. Thus, whilst one tree gave a proportion of less than 1 per 
cent., another gave a value of 6 per cent. In Grenada I obtained 
quite phenomenal results, the fruits of five trees examined yielding 
a proportion of 7| per cent, with two hypocotyls, none with three 
being observed. But the proportions varied greatly, the respective 
results for the different trees being 16, 11, 7, 3, 1 per cent. The 
rate of frequency obtained by Baron von Eggers in the tropics of the 



RHIZOPHORA MANGLE 



99 



New World was very small, namely, 3 per 1000 {Plant Dispersal, 
p. 450). 

The Length attained on the Tree by Seedlings of Rhizo- 
phora mangle. — In Jamaica, as in Fiji and Ecuador, I found that 
the average length attained by seedlings on the tree, the measure- 
ments being taken from the base of the plumule, was from nine to 
ten inches. In all three regions, when growing in sheltered situations, 
they may attain a length half as long again. But it would seem that 
this maximum is at times greatly exceeded in the New World. Thus 
I found washed ashore on the weather side of Tobago, mingled with 
much Orinoco drift, several seedlings sixteen to eighteen inches long, 
and in one case twenty-two and a half inches in length. It is quite 
possible, however, if these seedlings had been a long time afloat in 
the sea, that their hypocotyls may have grown in length, a subject 
discussed above. 

The Absence of Dimorphism in Rhizophora mangle in 
Jamaica and other West Indian Localities. — In different 
localities in the West Indies, as in Jamaica, the Turks Islands, and 
Grenada, I endeavoured to ascertain if Rhizophora mangle exhibited 
the dimorphism displayed by the species in Ecuador. In my book 
on Plant Dispersal (pp. 445, 487) it is shown that in Ecuador 
there are two forms : the one " mangle chico," ten to fifteen feet 
high, growing in the seaward and landward margins of the swamps ; 
the other " mangle grande," which attains a height of sixty or 
eighty feet and composes the interior of the swamp. The last in 
some of its characters approaches Rhizophora mucronata, the Asiatic 
species. However, after careful inquiry in the Black River and 
Savanna-la-mar districts of Jamaica, I could not discover any per- 
sistent evidence of dimorphism. Although there was often a con- 
siderable contrast in height and size between the Rhizophora trees 
fronting the sea and those growing in the midst of the swamp and on 
the banks of estuaries, the former frequently only ten or twelve feet 
high and the latter attaining heights of sixty or seventy feet, the 
floral characters as a rule remained much the same. Only in a few 
cases did there seem a tendency to the development of the " mangle 
grande " type in the taller trees. It may be that Rhizophora 
racemosa (a form of Rh. mangle where the stalk of the inflorescence 
branches two or three times), which was long ago differentiated by 
botanists, may answer to the " mangle grande " type. The two are 
separated in Hooker's Niger Flora. However, the " mangle chico " 
is evidently the West Indian form. The plants of the Turks Islands 
were all of this type, and, as far as examined, those of Grenada and 
Tobago. On the parts of the coast of Porto Rico visited by Dr. 
Millspaugh the tree " seldom attains a growth of over ten feet in 
height " {Plantar Utowano3, Pt. I.). In the West Indies I never 
came upon any seedless form of Rhizophora, such as I have described 
in the case of the 44 Selala " of Fiji {Plant Dispersal, p. 443). 

On the Influence of Varying Degrees of Salinity on the 
Station of Rhizophora mangle. — A promising field of inquiry 
would lie in the systematic determination with the hydrometer of 
the influence of varying degrees of salinity on the distribution of 



100 PLANTS, SEEDS, AND CURRENTS 



plants in the estuaries and coast swamps of tropical regions. An 
investigation on the lines of that pursued by Prof. Harshberger on 
the salt-marsh and estuarine plants of the New Jersey coast would 
yield valuable results (vide Proc. Amer. Philos. Soc, Sept. 1911). 
For such a study the true mangroves of the genus Rhizophora would 
offer abundant materials. Though I have made observations on 
this subject with reference to species of Rhizophora, and particularly 
Rh. mangle, in different parts of the tropics, they have been discursive 
in their nature, and, as will appear, they supply rather hints for 
further inquiry than conclusive and determinate results. 

In Fiji, where I made a special study of Rhizophora mangle, the 
American species, and of Rh. mucronata, the Asiatic species, I found 
that whilst they both throve at the coast, only the first named was 
also at home in the brackish water of the estuaries. This double 
station, in the coast swamp and in the estuary, was displayed by 
Rh. mangle in Fiji, in Ecuador, and in Jamaica. In all three localities 
I ascertained that the tree could live in the higher parts of an 
estuary where the water was at certain states of the tide quite fresh, 
and at others brackish or slightly salt. But my data showed that 
however well it might adapt itself to fresh- water conditions for some 
hours of each day, it would not be able to live in the parts of the 
estuary altogether beyond the reach of the sea-water. Typically, 
Rh. mangle is a tree of the coast swamp and of the mouth of an 
estuary where the sea- water has in a general sense much of its normal 
salinity. Its seedlings can be transported by the currents to islets 
in the open sea, where they give rise to mangrove colonies, such as 
are presented by the Florida sand-keys. If it is able to adapt itself 
to the slightly salt or even to the fresh water of the interior of an 
estuary, it is only for a portion of the day. Rh. mangle is primarily 
a plant of the typical salt-water swamp of the tropical sea border. 

Yet its adaptability to less saline conditions invites inquiry. As 
stated in my book on Plant Dispersal (p. 442), it extends in Fiji to 
the higher reaches of the estuaries, where the density of the water 
varies according to the state of the tide between 1-000 and 1*010. Its 
behaviour is the same in Ecuador. In the Guayaquil River it grows 
forty miles up the estuary, where the water is potable and has a 
density of 1*000, except at high water, when it is brackish (Ibid., 
p. 486). In the channels at the back of the city of Guayaquil, to 
which the sea-water has freer access, the water at high tide had a 
specific gravity of 1*014; and in response to the increased salinity 
there was a more typical development of the mangrove formation, 
Rh. mangle fronting the water with Laguncularia racemosa and 
Avicennia in the rear. In the case of the Santa Rosa River, which 
opens on the Ecuador coast near Puerto Bolivar, Rh. mangle, 
though abundant at the coast, failed altogether about ten miles from 
the mouth of the estuary, where the water was quite fresh during 
nine out of the twelve hours, being salt only in the latter part of the 
rising tide. 

In the Black River of Jamaica I obtained similar results in the 
month of January. In the company of Laguncularia racemosa this 
Rhizophora ascends the main channel of the estuary for two and a 



RHIZOPHORA MANGLE 



101 



half or three miles ; and though it thrives where the water has the 
density of fresh- water during most of the twenty-four hours, except 
towards high tide, when the hydrometer indicated 1-002 and 1*003, 
it disappears when the water is permanently fresh. In the Salt 
Springs branch of the estuary the same thing occurred. Rhizophora 
mangle grew on the banks for the first two or three miles of the 
ascent, when the specific gravity of the water varied between 1*000 
and 1.003; but it disappeared altogether from the river-banks a 
mile or two further up, where the water was permanently fresh. 
The mode of its disappearance was remarkable, the trees not only 
diminishing in numbers, but very markedly in size. It is thus 
described in my journal : " Whilst ascending from Salt Springs to 
the Blue Hole fine specimens of Rhizophora trees, fifty feet high, lined 
the banks in places for the first half-mile. After this the trees were 
scanty, and became smaller and smaller as we penetrated further into 
the Great Morass, until, at about a mile and a half above Salt Springs, 
the trees originally fifty feet in height, were reduced to shrubby, 
sickly-looking growths, and shortly disappeared." 

Probable Infiltration of Sea-water into the Interior of 
the Great Morass of the Black River. — The name of Salt 
Springs, which is given to one of the principal branches of the Black 
River estuary, would seem to indicate that salt water wells up in 
the midst of the Great Morass in which the place thus called lies. 
In spite of the name I could learn of no such phenomenon, but it 
is not unlikely that sea-water does penetrate for some distance 
through the lower portion of the dense mass of plant-growth that 
forms the surface of the morass. Beneath the plant-growth lies a 
platform of the rag-rock of the district, a limestone seemingly com- 
posed in the main of old reef detritus, and not infrequently bared to 
view. The Great Morass, the general vegetation of which is described 
later in this chapter, extends inland for five or six miles as the crow 
flies, and is raised but a few feet above the sea. There is some 
ground for holding, as is explained below, that the salt water ascends 
much farther up the river along its bottom than is indicated by the 
density of the surface-water. But, apart from this, it would be 
strange if the sea-soaked mangrove swamps of the coast, which are 
physically continuous with the inland swamps of the Great Morass, 
did not favour the landward infiltration of sea-water. 

In the case of the Machala plains on the coast of Ecuador, where 
low-lying districts extending several miles inland constitute the sea 
border, I have shown that this takes place on an extensive scale 
(Plant Dispersal, p. 485). Here there is continuity in the soil-cap 
between the mangrove belt of the coast and the arid plains miles 
inland. The rise in level being only a few feet, the effects of the 
sea-water infiltration are evident on the surface far from the coast 
in a saline efflorescence on the soil. The stages of the infiltration 
landward of sea- water are displayed : first, in the mangrove swamps 
a mile or two in width daily overflowed by the tide ; second, in the 
salt-encrusted mud-flats in their rear, which are overflowed only by 
the higher tides, and support plants like Salicornia, Sesuvium, and 
Batis maritima ; third, in the vegetated plains still farther behind, 



102 PLANTS, SEEDS, AND CURRENTS 



which extend for miles inland, and, though sufficiently raised above 
sea-level to be above the reach of the tides, are nevertheless soaked 
with sea- water, that displays its presence in the salt left by evapora- 
tion on the surface of the ground. On these plains, at a distance of 
four miles from the coast and probably extending much farther 
inland, there flourishes a dry jungle-type of vegetation of the xero- 
philous kind, such as Algaroba trees (Prosopis), cactaceous plants, 
and several sorts of prickly shrubs. 

Those who live near rivers in houses built on alluvial soil know 
that when the river is in flood the water rises through the basements 
of their dwellings long before the river overflows its banks. This 
is well illustrated in the delta of the Mississippi, as at New Orleans, 
where the graves have to be erected on the surface of water-soaked 
ground. When low-lying districts of alluvial formation front the 
sea, the salt water must often be found a short way below the surface 
far inland. 

It would, therefore, be a matter for surprise if the subsoil water 
of the low-lying region of the Great Morass in the Black River 
district of Jamaica did not often hold in solution much saline material 
at a distance of two or three or more miles from the sea border of 
the swamp. But little indication of the infiltration of sea-water in 
the subsoil might be offered by the surface-waters of the morass; 
and mangroves, thriving away from the coast in a seemingly fresh- 
water swamp, may actually have their roots immersed in a salt- 
impregnated substratum. 

It is not difficult to show, as I have already done, that on the 
banks of a river Rhizophora mangle gradually dwindles away, as one 
ascends the stream, until it disappears altogether when the water 
is permanently fresh. But away from the streams in the midst of 
the Great Morass, where the surface water varies in density only 
between 1*000 and 1*001, there occur in the Black River delta, a 
couple of miles from the coast, isolated belts of tall Rhizophora trees, 
fifty or sixty feet high, which seem strangely out of place in the 
midst of a dense growth of Typha. I was told by my coloured 
companions that these inland belts of Rhizophora are situated around 
shallow pools infested by alligators. I could not do more than 
examine the margin of one of these belts ; but I remarked the rela- 
tive thinness of the leaves of the trees. They would be worth a 
careful examination by a resident. It would seem probable that 
salt water here wells up through the swamp, or at any rate approaches 
the surface. 

The Underflow of Sea- water in Estuaries. — An important 
factor in influencing the stations of plants in tropical estuaries is to 
be found in the circumstance that whilst the surface water, more or 
less fresh in character, is running down, there may be an under- 
current of sea- water running up. Thus opposite Puna, at the 
mouth of the Guayaquil River, I found on one occasion that while 
the surface water with a density of 1*010 was running down, my 
thermometer, when lowered to a depth of two fathoms and more, 
was carried up-stream by a strong undercurrent, which extended to 
the bottom at a depth of seven fathoms. Evidently the sea- water 



RHIZOPHORA MANGLE 



103 



was making its way up the estuary beneath the down-flowing fresher 
surface water, but the differences in temperature were very slight. 
During the two days that we lay in quarantine off Puna the density 
of the surface water ranged between 1*004 and 1*016, being saltest 
after the tide had been running up for a while. Some time after 
the tide had commenced to " flow," the whole mass of the river 
water turned up-stream. The result of this delay in the backing of 
the water was that the duration of the up-going tide was shorter 
than that of the ebbing tide. This contrast increased with the 
ascent of the estuary, so that at Guayaquil, forty miles from the 
sea, the reversal of the downward current occupied only a short 
time. 

The undercurrent of sea- water ascending an estuary is a common 
feature in the regime of a river, and it is one that must have a 
definite relation with the stations of plants growing at the water- 
side. With this feature is doubtless to be connected the curious 
fact that the water may continue to rise after the ebb has begun at 
the surface. It is apparent that in a tidal estuary a multitude of 
lines of inquiry offer themselves to an investigator with the 
hydrometer. 

In some cases, however, valuable indications may be obtained 
from differences in temperature. When one finds in an estuary that 
the water at the bottom is warmer by some degrees than the water 
at the surface, the existence of an undercurrent of sea- water may be 
surmised. Suspecting that there was an up-current of sea- water 
below the surface fresh- water of the Black River estuary in Jamaica, 
I made some observations, at noon in the month of January, in the 
main stream between the bridge opposite the town and the junction 
of the Salt Springs River, a mile further up, the depth varying from 
three to three and a half fathoms. Having first ascertained that the 
temperature of the sea was about six degrees (Fahrenheit) warmer 
than that of the river, the sea being 80° and the river 74°, I proceeded 
to compare the surface and bottom temperatures of the river. A 
number of observations made in the part of the estuary above stated 
gave closely similar results, which I may sum up in the remark that 
whilst the downward surface-current of fresh- water (density 1*001) 
had a temperature of about 74°, the water on the river bottom 
showed a temperature of 78° F. Here it was evident that the salt 
water was ascending the river beneath descending fresh-water, and 
that the influence of the dissolved salts in the sea-water was more 
than sufficient to counteract the decrease in density due to its higher 
temperature. Within the mouth of the Salt Springs branch of the 
estuary the difference between the surface and bottom temperatures 
was only two degrees, and a little higher up there was none at all. 

The complicated Problems offered in the Thermometric 

AND HYDROMETRIC INVESTIGATION OF A TlDAL ESTUARY. A multi- 
plicity of considerations arise when we regard the influence on plant 
stations of the greatly varying conditions of temperature and salinity 
in different parts of a tidal estuary; and their complexity deepens 
when we contrast the regimes of different seasons. The whole 
subject of the economy of an estuary, as revealed by the thermometer 



104 PLANTS, SEEDS, AND CURRENTS 



and hydrometer, is here opened up, and it presents many very com- 
plex problems. It would be futile, however, to speculate now on 
the various working values to be assigned to the increase in density 
due to the fall in temperature and to the increase arising from dis- 
solved saline materials. We will leave the problems offered by this 
contest between the elements to the future investigator, and will 
content ourselves with the reflection that much light will be thrown 
on the conditions which determine the stations of plants in a tidal 
estuary by such a systematic employment of the hydrometer and 
thermometer as was exhibited in Prof. Harshberger's investigations 
on the estuarine plants of the coast of New Jersey. 

The Springs of the Black River Morass, as Illustrated by 
those of the Blue Hole. — It is likely that the numerous springs 
of fresh-water which well up in different parts of the Great Morass 
supply a large proportion of the water that the Black River dis- 
charges into the sea. One of the best known of these springs is the 
Blue Hole, which lies, as the bird flies, four or five miles from the 
coast, and is reached by way of the Salt Springs tributary, of which 
it is one of the main sources. These springs, which are distant about 
a mile from the foot of the neighbouring range of hills, issue in a 
funnel-shaped, well-like hole about forty feet deep and sixty feet 
across. The considerable body of water which here escapes is carried 
away in a stream, the channel of which is almost blocked by aquatic 
plants, that grow here in great luxuriance. On January 7, 1907, at 
noon, the temperature of the Blue Hole was 75-5-76° F. at the 
bottom, and 77° at the surface, that of the river below, which received 
its waters, being 76-77°. 

A rich growth of aquatic and semi-aquatic plants is characteristic 
of the large and copious head-springs of rivers in most parts of the 
world. Here under comparatively uniform thermal conditions, 
where the yearly range of the water-temperature often corresponds 
approximately to the limited range of the monthly means of the 
air-temperature in the shade, the aquatic plants thrive vigorously 
throughout the year. For the whole twelve months it is probable 
that the range of temperature of the water in which the vegetation 
around the Blue Hole is bathed would be only 75 to 82° F., which is 
the usual range of the monthly means of the temperature of the air 
in the lowlands on the south side of Jamaica. (See a paper by the 
present writer on the temperature of springs in the Journal of the 
Royal Meteorological Society, about 1895, and papers on river- 
temperature in the Proceedings of the Royal Physical Society of 
Edinburgh, 1896.) 

The plants grow in greatest profusion in the stream leading 
immediately from the Blue Hole. Largely occupying its channel 
and often carpeting the bottom are masses of Isnardia palustris, 
Hydrocotyle umbellata, Potamogeton plantagineus, etc. There also 
flourish here in the shallows Sagittaria lancifolia and a pretty yellow- 
flowered Utricularia. Pistia occidentalis fills up little recesses in the 
oozy banks, propagating its kind vegetatively with rapidity. In the 
river below Ceratophyllum demersum grows in the shallows. 

The Vegetation of the Black River District. — This may be 



RHIZOPHORA MANGLE 



105 



conveniently described under three heads : (a) the aquatic and semi- 
aquatic plants of the river and the riverside; (b) the plants of the 
Great Morass, a region of swamp traversed by the Black River and 
its tributaries ; (c) the plants of the mangrove formation. 

(a) The Plants of the River and the Riverside. — Lining the banks 
above the mangroves is a tall reed-growth of Cyperacece (Cyperus 
elatus, etc.) and Typha angustifolia, with which are associated 
Sagittaria lancifolia, which attains a height of four or five feet, 
Chrysodium vulgare (the Swamp Fern), a species of Jussi&a, Pavonia 
corymbosa (a malvaceous shrub), Polygonum glabrum, etc., all of 
which grow more or less in the water or in the swampy borders. In 
the shallows grow the Water Hyacinth (Pontederia) and Nymphcea 
ampla, the last covering the large expanses of water into which the 
rivers occasionally broaden out. Amongst the more or less sub- 
merged aquatic plants are Utricularia (near U. obtusa), Potamogeton 
plantagineus, Ceratophyllum demersum, Isnardia palustris, Hydrocotyle 
umbellata, etc. Pistias grow scantily in the recesses of the banks of 
the main channels, but are especially abundant in the vicinity of the 
springs that well up in different localities of the Great Morass, and 
nestling amongst them little floating masses of Azolla may be at 
times observed. 

(b) The Vegetation of the Great Morass in the Black River District. — 
This broad, savannah-like region, elevated but a few feet above the 
sea, extends some six or seven miles inland to the foot of the moun- 
tains. Looking down upon it from the slopes behind, one would 
imagine that one was gazing at some arid plain where clumps of tall 
palms serve to vary the monotony of a landscape in which Nature 
has been niggard in her ways. This notion would receive fresh 
colour when we observed the rivers winding through the plain and 
the dark green belts of trees that in places marked their courses. 
Yet we are not looking at a waste but at a swamp, where the ground 
is soaked with water as a sponge, where copious springs well up, and 
where the alligator finds a home. 

The tall palms are the Thatch Palms (Sabal umbraculifera), and 
they grow in the midst of a swamp- jungle largely composed of a 
reed-growth of Typha, Cyperaceae, and other similar plants. We 
should often find no footing in the marshy ground ; and if we wished 
to examine the district, we must pole along in a canoe through 
narrow channels more or less blocked by vegetation. In one place 
we should be traversing an area of several acres occupied only by 
Scirpus plantagineus, growing to a height of three feet, and sugges- 
tive in its appearance of an Equisetum. In another place we should 
find the surface carpeted with Herpestis monniera. A third locality 
would be appropriated by the Swamp Fern (Chrysodium vulgare). 
But more often the eye would rest on the tall reed-growth of grasses 
(Arundo, etc.) and sedges (Cyperus, etc.) and bulrushes (Typha) that 
monopolises most of the surface. Conspicuous amongst the swamp 
vegetation are the Pavonia trees, or rather shrubs (P. corymbosa) ; 
whilst, strangely enough, Conocarpus erectus, a plant typically 
halophilous in its station, is one of the most frequent among the smaller 
trees in this fresh- water morass in places where the ground is firmer. 



106 PLANTS, SEEDS, AND CURRENTS 



Coming to the vegetation of the banks of the Black River, as it 
winds through the Great Morass above the mangrove, the most 
conspicuous feature is presented by the trees that line its sides in 
places. This subject is dealt with at length in Chapter I., when dis- 
cussing the Black River as a source of drift, and I must refer the 
reader to that description for an account of a character of the 
Great Morass that was probably much more pronounced before the 
arrival of the white man. 

(c) The Plants of the Mangrove Formation. — The mangroves of the 
Black River district are mostly confined to the lower part of the estuary 
and to the part of the Great Morass that lies nearest to the sea. 
Whether in the swamps or at the riverside, they do not usually 
extend more than two or three miles inland. In both cases they 
present the same arrangement, the belt of Rhizophora mangle at the 
water-front being backed by a growth of Laguncularia racemosa and 
Avicennia nitida. In localities near the coast Bails maritima and 
Salicornia flourish on the mud beneath the mangroves. An account 
of my observations on Rhizophora mangle in this district will be found 
on an earlier page of this chapter. 

The Savanna-la-mar District of Jamaica. — This region in- 
cludes the Great Morass of Westmoreland, where most of the features 
of the Black River Morass are reproduced. I will here give the 
results of observations made during my sojourn of a week or two in 
the district. One of the most instructive journeys through the low- 
lying, swampy regions of Jamaica may be made from Savanna-la- 
mar to Negril, a traverse of fifteen or sixteen English miles. For the 
first third of the distance, where the mangrove-lined creeks run in 
far from the coast, one's attention is mainly occupied with the inland 
extension of Rhizophora, Laguncularia, and Avicennia, and with the 
large tracts of muddy ground exclusively occupied by Batis maritima. 
In the middle third we have left the salt-water swamps behind, and 
now traverse a region of fresh- water swamp much like that of the 
Great Morass of the Black River district. Here nourish Sabal 
umbraculifera, Typha angustifolia, Sagittaria lancifolia, Cyperacece, 
and others of the Black River marsh plants. In the last third we 
encounter the characteristic vegetation of the lower hills, with 
Grias cauliflora growing at the sides of the streams, but we meet 
the mangroves again on approaching Negril. Britton, who com- 
pares the Great Morass of Westmoreland with the Everglades of 
Florida, noted the presence here of Crudya spicata (Harshberger's 
Phyt. Surv. N. Amer., p. 678), which, as observed in the first chapter, 
is a riverside tree in the Black River Morass. 

Among the small rivers that discharge into the sea near Savanna- 
la-mar is the Cabarita. Here the mangroves, chiefly represented by 
Rhizophora mangle, ascend the stream for about a mile from the sea, 
being associated with Grias cauliflora at their upper limit. In the 
swampy land bordering the river, where the mangroves fail, flourish 
Typha angustifolia, Cyperus elatus (a tall, papyrus-like sedge), and 
Arundo saccharoides ; whilst Coix lachryma sometimes covers large 
surfaces of wet ground. The banks displayed more than one species 
of Polygonum, including P. glabrum, and a species of Commelyna was 



RHIZOPHORA MANGLE 



107 



especially frequent. The Water Hyacinth (Pontederia), Potamogeton 
fluitans, and Ceratophyllum demersum grew abundantly in the stream ; 
whilst occasional young Pistias and small portions of Azolla were to 
be observed on the surface. 

I ascended for about 100 yards Bowen's River, a small stream 
twenty-five to thirty feet across and infested by alligators, which 
lies about three miles east of Savanna-la-mar. Whilst Typha and 
Sagittaria grew on the borders, Polygonum glabrum, a pretty blue 
Commelyna, and Hydrocotyle umbellata flourished at the margins and 
in the shallows. Ceratophyllum demersum grew in dense submerged 
masses, and in shallow places near the banks the surface of the 
water was covered with Azolla. 

The Great Lake at Pondside near Black River. — This is a 
large sheet of fresh- water less than a mile in length and ranging, as 
I found, between one and a half and two and a half fathoms in depth. 
Alligators here find a congenial home. They lay almost submerged 
across the path of the canoe, and sank slowly as we approached. For 
this reason I could not examine properly the abundant, tall reed- 
growth at the margins, my little craft being frail and leaky, whilst 
my coloured companion was too much scared to be of use to me. 
Nymphcea ampla grew in abundance, for the most part in the shal- 
lows; but even in the centre of the lake solitary plants with very 
slender stems rose up to the surface from a depth of ten feet. Utri- 
cularias, not in flower, were associated with the Nymphaeas; and 
Potamogeton plantagineus thrived in all the shallower waters, with 
Sagittaria lancifolia at the borders. In marshy places, where springs 
rose up on the side of the lake, I noticed the Dumb Cane (Dieffen- 
bachia seguine). I visited this lake a few days after the great earth- 
quake at Kingston in January 1907, and was told that 44 the water 
rose up in large waves like the sea." 

The District of the Salt Lakes near Black River, Jamaica. 
— Bordering the sea-coast a few miles to the east of Black River lies 
the district known as the Salt Lakes. Here are a number of shallow 
salt-water lagoons in the midst of extensive mud-flats and swamps. 
A detailed topographical description would be here out of place ; but 
one may say that this region of lagoons is backed by the Great 
Morass, and that it is fronted by the sea-beach. The lagoons vary 
much in size, the largest being known as the Great Salt Lake, which 
is nearly a mile in length, and at the time of my visits in January 
1907 scarcely a fathom deep, the greatest soundings obtained being 
usually four or five feet. Separating the lagoons from the sea is a 
low strip of land varying in width between a few yards and a quarter 
of a mile. Under ordinary conditions, such as prevailed at the time 
of my visits, these lagoons are cut off from direct communication 
with the sea. The Great Salt Lake, it is true, has a narrow, tortuous 
channel leading to the coast, which is known as the Creek. But at 
ordinary times there is no passage here through the beach. How- 
ever, in the rainy months, as in May and October, when much of the 
Salt Lakes district is submerged by the waters draining coastward 
from the Great Morass, the waters force their passage and the Creek 
remains open for a while to the sea. But Nature is sometimes slow 



108 PLANTS, SEEDS, AND CURRENTS 



in giving relief to the submerged region, and the people of the neigh- 
bourhood then dig a trench through the beach for carrying off the 
surplus water. 

It is therefore evident that the hydrographical features of the 
district of the Salt Lakes vary greatly in different seasons. Although 
the drainage of the waters from the Great Morass is relatively small 
for most of the year, it is large in the wet months. After the rains 
the lagoons are greatly increased in size and their water is nearly 
fresh. During the dry months they shrink considerably and become 
very salt, the smaller lagoons being sometimes completely desiccated 
or reduced to scanty lakelets only a few inches deep. This alterna- 
tion between a state of high salinity and a condition when the water 
is almost fresh must have an influence on the distribution of the 
vegetation. 

When I visited this locality in the middle of January intermediate 
conditions prevailed, such as exist probably through the greater half 
of the year. Some of the lesser lagoons had dried up, being repre- 
sented by expanses of white mud. Others were reduced to ponds a 
few inches deep, the water being very warm and very salt. In the 
case of a greatly shrunken lagoon nearest to Paroti Point, the density 
and temperature of the water at midday were respectively 1*031 and 
88° F., the values for the sea at the same time being 1*026 and 79° F. 
In the larger and deeper lagoons the contrast between their salinity 
and that of the sea was slight. Under similar conditions of tempera- 
ture the salinity of the water was 1*028 and that of the sea 1*026. 
At first sight the Salt Lakes district would appear to be well fitted 
for the salt-pan industry, but the fresh- water from the great inland 
swamps, especially after the rains, would probably prevent the 
success of such an undertaking. 

General Character of the Vegetation of the Salt Lakes 
District. — Avicennias among the trees and Salicornias amongst the 
lesser plants form the predominant features of the vegetation occupy- 
ing the extensive expanses of white mud that give the character to 
the district of the Salt Lakes. Then come the mangroves at the 
borders of the larger lagoons, and here the same Avicennia (A. 
nitida) takes its place with Rhizophora mangle and Laguncularia 
racemosa in the swamp. Around the shores of the Great Salt Lake 
the Rhizophoras and the Avicennias are, however, the most frequent, 
sometimes the one, sometimes the other, usurping the lake's margins. 
All three mangroves thrive in the creek which leads from the beach 
to the lake. In the smaller lagoons, where the water has been 
reduced to a depth of a few inches and has a greater salinity, the 
Rhizophoras disappear from the mangrove belt, leaving the Avicen- 
nias and Laguncularias in possession of the borders of the partially 
desiccated lake. On the expanse of exposed mud-flats Salicornias 
and Batis maritima thrive. When the water has evaporated away 
and only a shallow depression indicates the original lagoon, the 
Laguncularias in their turn disappear, and Avicennias with Salicornias 
and Batis maritima alone remain. 

Avicennias grow in this district under all the various soil-conditions 
that are presented, whether in the salt-water swamp, in the wet salt 



RHIZOPHORA MANGLE 



109 



mud on the margins of the lagoons, in the places removed from the 
lagoons where the saline mud dries on the surface in the sun, in the 
neutral ground between the sandy beach and the mud-flat where the 
soil is loamy and beach plants mingle with those of the mud-flats,- 
or, lastly, on the borders of the great inland fresh-water swamps, 
where they come in touch with the plants of the Great Morass. In 
all these stations they have different associates : herding at one time 
with Rhizophoras and Laguncularias in the swamps; at another 
growing with Salicornias on the soft mud-flats; at another with 
Jacquinia armillaris, Conocarpus erectus, etc., where the saline mud 
hardens on the surface in the sun ; at another time side by side with 
beach plants like Coccoloba uvifera, Dodoncea burmanni, and Ernodea 
littoralis, where the soil is loamy near the beach; and at another 
time amidst the tall Sabal palms (S. umbraculifera) and the Cyperacece 
which mark the outskirts of the inland region of fresh- water swamps. 
If we except Conocarpus erectus, there is no plant in the Salt Lake 
district that displays so much adaptability to the various conditions 
as Avicennia nitida. 

Conocarpus erectus is similarly associated here with the mangroves 
at the borders of the lagoons, with the plants of the exposed mud- 
flats, and with those of the sandy beach ; but its powers of adaptation 
are not so conspicuous on account of its being much less frequent 
than Avicennia nitida. Its adaptability to different stations is 
discussed more in detail in the separate treatment of the plant. 

Several other plants occur in this district, but they are usually 
not common enough to give character to the vegetation. One may 
refer, however, to the Silver Thatch palm (Thrinax argentea), a small 
palm, three to nine feet high, which is certainly characteristic of the 
neutral ground between the mud-flats and the sandy beach on the 
seaward side and the inland swamps in their rear. Portulaca hali- 
moides, an interesting little plant with woolly flowers and only two 
or three inches high, grows in places on the salt white mud, especially 
where the ground, though moist beneath, is baked on the surface by 
the sun's heat. Jacquinia armillaris (L.) is a small tree or shrub 
that is very common on the saline mud of the flats, growing gregari- 
ously and exhaling from its flowers a penetrating odour like that of 
bitter almonds. This is J. barbasco of Mez (Das Pflanzenreich, 
Theophrastacece, 1903). It is a littoral plant widely spread in the 
West Indies. Its hard seeds, which are 5 mm. in length, have no 
buoyancy, and are probably dispersed by birds, though the dryish 
berry would not seem to be especially attractive. 

Summary 

1. As supplementing his observations on Rhizophora in the Pacific 
islands, the author adduces additional facts from other sources to 
confirm his previous conclusion that the lapse of a period of nine or 
ten months between fertilisation and the fall of the seedling is typical 
of the genus (p. 96). 

2. He presents data from his West Indian experiments to show that 
Rhizophora seedlings, after detachment from the tree, can at times 



110 PLANTS, SEEDS, AND CURRENTS 



retain their vitality in the dry condition for five months, an implica- 
tion arising from his results being that the seedlings, when they fall 
into the sea, would often continue their hypocotylar growth in length 
for an inch or two (pp. 96-98). His observations in the Pacific on 
the proportion of germinating fruits of Rhizophora mangle possessing 
more than one seedling, and on the extreme length of the hypocotyl, 
are here supplemented (pp. 98-99). 

3. He was unable to discover in the West Indies any persistent 
evidence of the dimorphism observed by him in Rhizophora mangle 
in Ecuador, nor did he come upon any seedless form of Rhizophora 
corresponding to the " Selala " of Fiji (p. 99). 

4. There are next given the results of a number of observations 
made in the West Indies, Ecuador and the Pacific islands on the 
influence of varying degrees of salinity on the station of Rhizophora 
mangle (pp. 99-101). 

5. Remarks are then made on the infiltration of sea- water into the 
interior of the Great Morass of the Black River district in Jamaica, 
and in this connection is noted the occurrence of colonies of Rhizophora 
mangle in the midst of this great swamp (pp. 101-102). 

6. The underflow of sea- water up tropical estuaries is regarded as 
an important factor in determining the stations of estuarine plants, 
and the subject is illustrated by the cases of the Black River in 
Jamaica and of the Guayas or Guayaquil River in Ecuador (p. 102). 
In this matter Prof. Harshberger's hydrometric and thermometric 
observations on the stations of plants in the tidal estuaries of New 
Jersey afford instructive lessons for similar investigations in tropical 
estuaries (pp. 103-104). 

7. Attention is directed to the numerous large fresh-water springs 
that well up in the midst of the Black River Morass, and to the rich 
growth of aquatic plants at their borders (p. 104). 

8. The author then deals at length with the vegetation of the 
Black River district, especially of the Great Morass, as well as of the 
similar region of swamp around Savanna-la-mar (p. 105). He also 
describes the vegetation of the Great Lake at Pondside near the 
Black River (p. 107). The physical and botanical features of the 
Salt Lakes in the same neighbourhood are treated in detail (p. 107). 



CHAPTER VI 



THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS 

In Chapter I. special prominence is given to the analysis of the 
larger foreign drift of the Turks Islands. It is now proposed to deal 
with each plant in the order of frequency of their fruits or seeds in 
the stranded drift of this small group, the several plants being treated 
often at length, from the standpoint of distribution. This will 
afford an opportunity of discussing the various interesting problems 
which these plants raise. 

ECASTAPHYLLUM (?) 

These legumes, which are amongst the most frequent of the fruits 
in the larger drift of the Turks Islands, have some of the characters 
of those of Ecastaphyllum, but are certainly not those of E. brownei 
(Pers.), a common West Indian littoral small tree or shrub. They are 
1 J— 1§ inch long, broadly oval, compressed, and have a shining 
reticulate epidermis. The single seed has thin, pervious coverings ; 
but in no case did I come upon one that was sound, all of them being 
in various stages of decay. 

Spondias lutea, Linn. (Hog Plum) 

Few fruits are more frequently represented in the beach-drift of 
the West Indies and of the Pacific and Atlantic coasts of tropical 
America than those of this tree. It is not, however, the fleshy drupe 
but its hard "stone" invested by a thick fibro-suberous covering, 
that is here found. These " stones," which are oblong in form and 
usually 1-1 J inch in length, float very buoyantly, and in their weather- 
beaten condition amongst old drift might be even taken for old 
corks rounded by the waves. 

The trees grow in open wooded districts, both inland and at the 
coast, and not uncommonly they are frequent at the riverside, as 
in the case of the Black River in Jamaica, or they grow in numbers 
on the slopes of a river valley, as I noticed in Tobago, or they may 
be found amongst the vegetation bordering the beach, as I observed 
in Grenada and Trinidad. Writing of the tree in Jamaica at the end 
of the seventeenth century, Sloane says that it was found every- 
where in the lowland woods and in the savannahs (II., 127). In 
Jamaica it is associated in the open inland woods with such trees 
as Cedrela odorata (Jamaican cedar), Pithecolobium filicifolium 

111 



112 PLANTS, SEEDS, AND CURRENTS 



(bastard tamarind), and Swietenia mahogani (mahogany), and in 
Cuba it has the same associates in the open forests that grade into 
the savannah formation. But in Cuba it also grows in the denser 
forests on the slopes of the river valleys (Fernow, etc., quoted by 
Harshberger, pp. 675, 676). 

The fruit, however, is too coarse to be palatable for man, but it 
is much appreciated by pigs, and from this circumstance it derives 
its popular name. As the fallen fruits lie on the ground they lose 
their fleshy covering; and the air-dried " stones " are so light that 
in places where the trees abound they may be seen gathered together 
by the strong winds. On a hillside in Tobago during the heavy rains 
I noticed that the 44 stones," which lay in quantities on the ground, 
were being gradually washed down the slope into the river below. 
The " stone" usually displays four or five cavities, each containing a 
seed. The seeds retain their freshness for years in my drift- collection, 
and this is evidently true of those in the beach-drift. However 
weather-beaten their appearance, it was never difficult to find 
44 stones " containing some sound seeds in the old drift, whether on 
a beach in Jamaica, where the trees are abundant, or on the shores 
of the Turks Islands, where they do not grow. 

On account of their great buoyancy the 44 stones " at first appear 
well suited for transport across the Atlantic. But the fact that I 
had found no record of their occurrence amongst West Indian drift 
stranded on European beaches led me to investigate the matter. 
As a result, I found that their floating powers were insufficient for 
the purpose of an Atlantic traverse in the Gulf Stream drift. In 
addition, it proved to be more than doubtful whether the seeds would 
retain their germinative powers after a flotation of more than a few 
months. I made an experiment on a number of drift specimens 
that preserved their sound condition. The indications were that 
although about half still floated after seven months in sea-water, 
they were sodden through their substance, floated heavily, and had 
decaying seeds. The limit of the period during which the germinative 
capacity is preserved in a passage across the sea seemed to be two 
or three months. Although the 44 stones " would be unable to 
survive the long passage of a year or more that would be involved in 
an Atlantic traverse from the West Indies in the Gulf Stream drift, 
they would, as far as their buoyancy is concerned, be well able to 
perform the passage of two or three months from the West Coast of 
Africa to Brazil in the Main Equatorial Current, and the seeds would 
probably retain their germinative powers. 

In the Turks Islands the 44 stones " were to be noticed, often in 
numbers, on all the cays where the drift was able to gather. They 
presented themselves among the drift on almost every beach in the 
West Indies that I examined, as on the north and south coasts of 
Jamaica, on the north and south sides of Trinidad, in Tobago, and 
in Grenada. It is many years since they were identified at Kew 
in a collection of seed-drift made by Morris in Jamaica (Chall. Bot., 
IV., 299). They are to be observed in the floating drift of rivers, 
as in the Black River of Jamaica, or stranded in numbers at their 
mouths, as in the case of the White River of the same island. It is 



FOREIGN DRIFT OF THE TURKS ISLANDS 113 



on the beaches that line the coast in the neighbourhood of estuaries 
that the " stones " of these fruits are most abundant. 

On the Pacific shores of tropical America they would seem to be 
equally abundant, whether afloat in the estuaries or cast up on the 
beaches. Thus, I found them in the Guayaquil River in Ecuador 
and on the beaches of the Ecuadorian coast towards the Peruvian 
border. They came under my notice on the beaches at Panama 
and afloat in a neighbouring estuary, and it may be added that they 
were gathered by me from the beach at Colon on the Atlantic side 
of the isthmus. 

The distribution of the tree over the greater part of the West 
Indian region, as well as on the Pacific and Atlantic borders of tropical 
America, derives new interest from the circumstance that the tree 
occurs on the tropical coast of West Africa. As before remarked, 
the " stones " are fitted for carriage in the Main Equatorial Current 
from West Africa to Brazil, and the seeds would probably preserve 
their capacity for germination. The difficulty, however, is that this 
tree is not a truly littoral plant. It may grow amongst the trees 
bordering a beach ; but it is more at home in an inland station on a 
hillside or near a river bank. It is, in fact, the river that as a rule 
brings the floating " stones " down to the coast before giving them 
over to the agency of the currents. 

Although I have gathered a large number of the stranded " stones " 
on beaches, I have never found one showing germinating seeds. In 
such an event, however, the young plant would certainly fail to 
establish itself. The " stones " are so extremely light that, as I have 
observed in the Turks Islands, the strong winds are able to blow them 
off the beach into the bush behind, where more favourable conditions 
might be found, though not in this particular group. Land crabs, 
also, that frequent the beach, might often carry them off and bury 
them in their burrows. 

It is likely that the spread of this tree within the same land area 
is assisted by the facility with which it roots when stakes are placed 
in the ground. The wood is very light, and it is possible that the 
trunk or a branch floating in a river may on stranding be able to 
establish itself on the bank. Sloane observes that it " grows easily 
by the branch " (II., 127). Under the head of Growing Stakes or Live 
Fences in Jamaica, this tree is mentioned in association with several 
others in Note 31 of the Appendix to my book on Seeds and Fruits. 

Hippomane mancinella, L. (Manchineei) 

Few plants seem to be better fitted for dispersal by currents than 
this littoral tree, which is widely spread over the tropics of the New 
World, occurring not only throughout the West Indies and on the 
Atlantic coasts of the mainland from Mexico to Venezuela, but also 
on the Pacific side. 

Pax, in his recent memoir on the section of the Euphorbiacea?, to 
which this plant belongs (Euphorbiaceo3-Hippomaneo3, Das Pflan- 
zenreich, IV., 147, V., 1912), only implies its occurrence on the Pacific 
side in the case of Costa Rica ; but doubtless he includes both coasts 
i 



114 PLANTS, SEEDS, AND CURRENTS 



of Mexico in his statement of the general distribution. Harshberger 
(p. 229) merely names Mexico, Central, and South America, without 
particularising the Pacific coast. However, I found it growing at 
Panama by the beach, and in all probability it is common on many 
parts of the Pacific coasts of Central America. Grisebach mentions 
Panama, but without distinguishing locality. It is a native of most 
of the West Indian islands, large and small, from Cuba to Trinidad, 
as enumerated by Grisebach and Pax. It extends north to South 
Florida and to the adjacent islands of the Bahamas, such as Andros 
and Abaco (Millspaugh), and reaches Venezuela to the south. As 
Pax suggests, its absence from certain localities may be due to its 
extermination on account of its poisonous nature. 

A few remarks on its station may now be made. Wherever I 
came upon it, as at St. Croix, Tobago, Grenada, and Panama, it was 
growing with the trees bordering the beach on sandy soil. Grisebach 
only refers to its station in the case of Trinidad, where it grows " on 
the sandy sea coast." Pax characterises it as a plant of the coast- 
lands and as often growing on rocky ground. Millspaugh says that 
it grows in coppices and on scrubland in the Bahamas. In South 
Florida, according to Harshberger (p. 230), it grows away from the 
coast, being one of the trees of the " hammocks." This is the name 
given to isolated patches of vegetation of varying extent that are 
scattered as islands in the everglades and pine forests, and are held 
to represent an ancient system of sea-washed keys, which existed 
during the later Tertiary and received their plants from the Bahamas. 
The " hammock," as we learn, is a refuge for nearly all the flowering 
plants that are common to the West Indies and the North American 
mainland. Though most of the trees and shrubs named by Harsh- 
berger grow in the coastal plains of the West Indies, few seem to be 
characteristic littoral plants; and for this reason the hammock 
scarcely appears to have become a sanctuary for typical strand 
plants in any number. 

The very poisonous nature of the milk-sap is well known; yet 
it is observed by Pax that some men possess an immunity in this 
respect. When at Panama I experienced severe pain for several 
hours through allowing the sap of the fruits to come in contact with 
my bare legs, extensive blistering resulting. It is probable that 
there is a substratum of truth in the fable that fatal effects arise from 
sleeping under the shade of this tree. The experiment made in the 
West Indies by Jacquin, who remained unhurt after standing naked 
for some hours under a tree, whilst the rain fell through upon him 
(Hooker's edition of the System of Botany of Le Maout and Decaisne, 
1873, p. 697) scarcely seems conclusive. The night dew dropping 
slowly from the leaves would be much more likely than the rain- wash 
to produce injurious effects. 

I made the acquaintance of this tree in different islands, as in 
St. Croix, Grenada and Tobago. I did not find it in the Turks Islands, 
although, according to Dr. Millspaugh, it has been collected there 
(see reference in the chapter on the flora of this small group). Its 
place is taken on Grand Turk by a small euphorbiaceous tree or 
shrub, not unlike it in habit, perhaps a species of Sapium, which has 



FOREIGN DRIFT OF THE TURKS ISLANDS 115 



the same popular name, and possesses, according to the inhabitants, 
the same dangerous qualities. The absence from the Turks Islands 
of the true Manchineel could scarcely be attributed to its extermina- 
tion by the islanders in the isolated uninhabited cays. Although it 
grows in Key West, off the Florida coast (Pax), we learn from Dr. 
Millspaugh's paper before quoted that it was not discovered by 
Mr. Lansing during his methodical examination of all the sand keys 
lying west of that island. The vegetation there is mainly littoral, 
and in many islets it is exclusively so. Several of the keys are little 
more than sandbanks, and the question of extermination by man 
could not be raised. It would thus appear that although, as shown 
below, the fruits of the Manchineel must be amongst the drift first 
stranded on new land in this part of the world, the tree is one of the 
last to establish itself. I never remember to have come upon a 
germinating fruit in the beach-drift of any locality, although examina- 
tion always showed that some of the seeds were sound. It may be 
that the intervention of certain land crabs is necessary, and that 
germination only occurs after the fruit has been stored in their burrows 
beyond the reach of the sea. Sloane, in the account of his voyage to 
Jamaica (II., pp. 4, 7), throws some light on this point. He says that 
goats feed on the fallen fruit greedily, and he was shown trees that 
had grown from seeds dropped in their dung. 

I come now to discuss more in detail the fitness of these fruits 
for dispersal by the currents. (I may add here that the fruits are 
illustrated in the memoir of Pax before named.) On account of 
the station of the tree by the beach, the fallen fruits, as I had several 
opportunities of observing, are liable to be picked up by the waves 
and carried out to sea. Should the fresh fruit, which is rather like 
a crab-apple in size and appearance, fall at once into the water, 
experiments show that it will remain afloat. But more often it loses 
its soft outer covering whilst lying on the sandy soil ; and in so doing 
its buoyant capacity is greatly increased. The bared fruit gathered 
after drying on the ground consists of a hard " stone " deeply grooved 
and covered with a thick layer of cork-like, air-bearing tissue. Neither 
the "stones" nor the seeds inside have floating power, the buoy- 
ancy being due to the investing material. These dry, bared fruits 
evidently can float for many months. Some of them kept in sea- 
water for five weeks showed no signs of sinking, all of them floating 
as buoyantly as when the experiment began. The stone usually 
has about six loculi, but not more than half contain sound seeds, 
the others being much contracted in size. Locked up within the 
woody endocarp, the oily seeds maintain a moist condition for years. 
After eight years, the seeds of some fruits gathered by me at Panama 
seemed quite fresh; whilst the fruits of the Turks Islands beach 
drift, which may in some cases have been lying there for years, as 
a rule appeared sound. 

It is, therefore, not surprising that the stranded fruits of the 
Manchineel came under my notice in nearly every place where the 
beach drift was systematically examined. At Panama, in Jamaica, 
St. Croix, Tobago, Grenada, Trinidad, and in the Turks Islands these 
fruits formed a regular constituent of the drift, and often in numbers. 



116 PLANTS, SEEDS, AND CURRENTS 



In several cases the tree was growing in the vicinity, but in Jamaica, 
though the bared fruits were to be frequently observed on the beaches, 
I never came upon the tree, though, according to Grisebach and Pax, 
it exists in the island. In the Turks Islands, as before remarked, 
the tree does not grow, yet the fruits occurred on almost every beach, 
and made up quite 10 per cent, of the larger drift. Wherever in 
this locality the drift had been able to gather, some of them were 
to be found, whether on Grand Turk and Greater Sand Cay, lying 
at the north and south extremes, or at Eastern Cay, the most wind- 
ward island of the group. As far as I can ascertain, these fruits have 
not been recorded amongst the West Indian drift stranded on the 
shores of Europe ; but it seems highly probable that they sometimes 
reach those coasts. 

Terminalia catappa, L. 

Since this tree was originally introduced into the New World, 
I need only refer to the fact that its dispersal by currents has long been 
known in the tropics of the eastern hemisphere, where it frequents 
the coasts, both insular and continental. In the writings of Schimper, 
Hemsley, Ernst, and others (including, I may venture to add, my 
own), it is frequently referred to in this connection. We learn from 
the observations of Treub, Penzig, Ernst, and their associates that 
its drupaceous fruits were amongst the first stranded on Krakatau 
after the desolation of its surface by the eruption of 1883, and that 
its young trees were amongst the earliest to establish themselves 
near the beach. 

In the warm regions of the New World it is now widely distributed, 
a work originally begun by man but since extended by the currents, 
especially in those localities, as in the island of Grenada and at 
Colon, where it has resumed its littoral station. In Grenada I found 
it bordering the beach in the company of Coccoloba uvifera, Hippo- 
mane mancinella, and Hibiscus tiliaceus. According to the data given 
by Harshberger, in his work on North America (p. 686), it grows 
characteristically among the trees lining the beach in the Virgin 
Islands in association with Coccoloba uvifera, Hippomane mancinella, 
Thespesia populnea, etc. 

Its fruits came under my notice in the beach-drift of Jamaica, 
Colon, and the Turks Islands. In the last-named locality they are 
abundant and occur on almost every beach where drift collects, 
always bared of their outer fleshy covering, and nearly always in a 
much weathered condition, but in most cases containing a sound 
seed. As is well described by Schimper in his Indo-Malayische 
Strandflora (p. 170), this drupaceous fruit owes its floating powers 
to a thick layer of cork-like buoyant tissue that invests the " stone," 
none of the other materials possessing independent buoyancy. 
The subject of the floating capacity of the fruits of the genus is fully 
discussed in my work on Plant Dispersal. 

Although Grisebach, Hemsley and other authorities agree in regard- 
ing this tree as introduced into the New World, it is remarkable 
that about a third of the total number of species in the genus, as 
indicated in the Index Kewensis (132 in all), are confined to America, 



FOREIGN DRIFT OF THE TURKS ISLANDS 117 



of which by far the greater number are tropical South American. 
But the endemism displayed in oceanic islands in the Indian and 
Pacific oceans, as well as in the West Indian islands, is very remark- 
able. The Mascarene Islands, Mauritius, the Andaman and Nicobar 
groups, the Fijian, Samoan, and Tongan archipelagos, Cuba, Jamaica, 
and even the Bahamas (Harshberger, p. 330), all hold one or two 
peculiar species of Terminalia. If we were to look for the home of 
Terminalia catappa in a region where the genus is best represented, 
we should find it in the New World, particularly in South America. 
The New World, we might imagine, ought to have been able to 
provide its own wide-ranging littoral species; and it seems strange 
that human agency should have had to intervene in the matter. 
However, the distribution of the genus presents many problems 
that cannot be dealt with here. 

Entada scandens, Benth. 

This plant is discussed at length in my two books, Plant Dispersal 
and Studies in Seeds and Fruits. In the first named it is regarded 
from the distribution standpoint. In the second, the germination 
process, the various stages in the maturation of the seed, and the 
development of its impermeability, are dealt with in much detail. 

The great floating powers of the seed have long been known, as 
well as its ability to retain its germinative capacity after being 
stranded on the European side of the Atlantic. The white, softish, 
full-sized moist seeds of the green legume possess no buoyancy. This 
capacity is acquired during the shrinking and hardening stage, being 
due to the large cavity produced by the bending outwards of the 
cotyledons as they dry, the materials of the typical dry seed having 
no floating power. 

The initial buoyancy of the seeds when recently detached from the 
plant is indicated by the results of experiments made in Fiji and 
Ecuador (Plant Dispersal, p. 181), from which it is inferred that 
quite 50 per cent, sink in sea-water and about 70 per cent, in fresh- 
water. In a recent experiment made in Jamaica the proportion of 
non-buoyant seeds in freshly gathered material was much smaller, 
only 20 per cent, sinking in sea- water and 30 per cent, in fresh-water. 
This variation in the initial buoyancy is due to the variation of the 
conditions attending the shrinking and drying process, which would 
probably be less complete in shady humid forests than in drier, 
exposed situations. From curiosity I tested the buoyancy of a 
hundred seeds with sound coverings that had been brought by 
currents and stranded on the Turks Islands. Of these, all but five 
floated in fresh-water and all but one in sea-water, the last named 
having from some cause lost its buoyancy. In my previous work 
on Seeds and Fruits it is shown that loss of impermeability may in 
time be induced through some initial defect in the cuticle. 

The seeds form a frequent constituent of beach-drift in the warm 
regions of the New World. Amongst localities in which I found them 
may be mentioned Ecuador, both sides of the Isthmus of Panama, 
Jamaica, and the Turks Islands, but not in Trinidad, Tobago, or 



118 PLANTS, SEEDS, AND CURRENTS 



Grenada, for reasons given below. In Jamaica I found them at 
various places, but only on the north coasts; but since they were 
obtained by Morris amongst the stranded drift near Kingston, it is 
evident that they may also be thrown up on the south side (ChalL 
Bot., IV., 302). In the Turks Islands they were frequent on every 
beach that held drift. 

The distribution of the plant in the New World is peculiar. It is 
found in Jamaica and probably also in Cuba, Haiti, and Porto Rico, 
and occurs on both coasts of Central America. But it is absent from 
the Bahamas, and though existing in the northern islands of the 
Lesser Antilles, as in Guadeloupe, it has not been recorded from the 
southern islands and from Trinidad. The implication of the absence 
of its seeds from the beach-drift of Trinidad and the adjacent islands 
off the Spanish Main is that it is not to be found in the neighbouring 
portion of the South American continent, that is to say, in the regions 
drained by the Orinoco and the large rivers of the Guianas. In these 
continental regions its place, though not its station, is taken by two 
or three other species. 

Of these, probably the most typical is Entada polystachya, a plant 
which I have discussed at length from a particular standpoint in 
my Studies in Seeds and Fruits. This species, which has much 
smaller non-buoyant seeds, has its home, according to Grisebach, in 
the Lesser Antilles from Dominica to Trinidad, as well as on the 
adjacent South American mainland, and, strangely enough, also in 
Panama. It grows away from the beach and often on trees by 
the side of rivers. It is not represented in the beach-drift, its 
seeds possessing no floating power, and evidently it could only be 
dispersed by currents through the agency of the separate joints 
into which the pod breaks up, the buoyancy of which could not be 
great. 

With regard to the absence of Entada scandens from Trinidad and 
the neighbouring islands of Tobago and Grenada, I may say that it 
is not represented in Hart's Herbarium List for Trinidad. Mr. Broad- 
way, who had an experience covering several years of the flora of 
this region of the West Indies, told me that it has not been found 
there. The only localities given by Grisebach are Guadeloupe and 
Jamaica, but the presence of its seeds in such quantities on the 
Turks Islands beaches indicates that it must be at home in San 
Domingo and Porto Rico, from which the seeds are in all probability 
derived. Its seeds occur in the drift on both sides of the Isthmus 
of Panama and on the beaches of Ecuador, and the plants grow in 
the woods at the back of the coasts in those regions. 

Grisebach, when referring to the station of Entada scandens in 
Jamaica, says that it is common in mountain woods; and it was 
usually in that station that I found it. But it may survive on trees 
beside streams and ditches in districts where the woods have long 
since been mostly cleared away for cultivation, as at Moneague. The 
greatest altitudes above the sea at which the plant came under my 
notice in Jamaica were on the slopes of Mount Diablo at 2000 feet, 
at Pallet at nearly 2000 feet, and at New Find near Lumsden at 
about 1500 feet — the two last localities being in the mountains at 



FOREIGN DRIFT OF THE TURKS ISLANDS 119 



the back of St. Anne's. In the Pacific Islands it is a characteristic 
plant on the trees lining the beaches and the estuaries. 

Two critical facts present themselves in the New World with 
reference to the distribution of this plant over the warm region of 
the globe. In the first place there is its occurrence on both the 
Atlantic and Pacific borders of Central America. As I pointed out 
in my work on Plant Dispersal, this does not compel us to assume, 
as in the case of the mangrove flora, that the plant's present distribu- 
tion in the New World antedates the emergence of the Panama 
Isthmus. Frequenting, as it does, not only estuarine regions but 
also mountain woods inland, it can be at once perceived that, given 
its occurrence in the interior of a region like the Isthmus of Panama, 
the seeds of plants growing on the same " divide " could be carried 
by rivers to both the Atlantic and Pacific borders. The seeds are 
often found in river-drift in different parts of the world. Thus I 
found them not only in estuaries on both sides of the Panama Isthmus, 
but also in the Guayaquil River in Ecuador, and in the estuaries 
of Fiji. 

The second critical fact of distribution is that whilst Entada 
scandens grows on the West Coast of tropical Africa, it is absent from 
the corresponding portions of South America (Venezuela to Brazil) 
and from the neighbouring West Indian islands, such as Trinidad 
and Tobago. It is certainly strange that seeds, which are trans- 
ported in the Gulf Stream drift to Europe in a sound state, have 
not been carried by the Main Equatorial Current from the Gulf of 
Guinea' to the South American mainland. As described in Chapter III., 
this is the direct track of many of the bottles thrown overboard in 
this current in mid-Atlantic. Whilst a West Indian seed would 
require a year or more to reach the coasts of Europe, it would accom- 
plish the passage from West Africa to Brazil in the Main Equatorial 
Current in from two to three months. A great deal, of course, 
depends on the distribution of the plant on the African coast. If it 
does not grow much south of Senegal and the Gambia, its seeds would 
be carried across the Atlantic in the North Equatorial Current, 
and would not strike the South American mainland. It is pointed 
out in Chapter III that bottle-drift from the latitude of Cape Verde 
only reaches the Lesser Antilles and the islands north; and it is 
not improbable that we have here an explanation of the peculiar 
distribution of Entada scandens in the New World. In other words, 
its range in tropical America may prove to be determined through 
the arrangement of the equatorial currents by its distribution in 
tropical West Africa. 

It may be that Entada scandens has not been for many ages a 
denizen of the New World. So little does it figure in the floras of 
the larger West Indian islands that the American botanical explorers, 
so freely quoted in Harshberger's great work, rarely seem to have 
recorded it. Yet it probably occurs in all these large islands. It is 
almost certain that the numbers of these seeds thrown up on the 
beaches of the Turks Islands are derived from Hispaniola, Porto 
Rico, and the northern islands of the Lesser Antilles, since the 
plant is not represented either in the drift or in the floras of the 



120 PLANTS, SEEDS, AND CURRENTS 



southernmost islands and of the adjacent continental regions of 
South America (Venezuela to Brazil). 

Yet a different standpoint may be needed when we come to regard 
the distribution of the genus. About a score of species are known, 
of which about a fourth are confined to the New World and about 
two-thirds to Africa and Madagascar, whilst Burma holds a species of 
its own. The indications are that, as a genus, Entada belongs to 
the tropics of both the eastern and western hemispheres, and that, 
however effective oceanic currents may have been in dispersing 
a particular species (E. scandens) around the globe, we must look 
elsewhere for the explanation of the range of the genus. In this 
respect Entada falls into line with a multitude of tropical genera 
shared by the Old and the New World. 

A word may be said here respecting the spread of Entada scandens 
to the interior of continents, as, for instance, to the Himalayan 
region and to the lake district of Africa. It is quite likely that man 
has often here played a part, but it is probable that large animals 
have also taken a share in the dispersal. We know that camels 
and ostriches will at times swallow almost anything; and although 
such creatures would scarcely frequent localities where Entada 
scandens is at home, yet it is noteworthy that there is in the Kew 
Museum an entire seed of this plant, measuring about 1 J inches across, 
which was removed from the caecum of a rhinoceros from Chittagong 
that died in the Zoological Gardens of London. 

MUCUNA URENS, DC, AND AN ALLIED SPECIES, PROBABLY MUCUNA 
ALTISSIMA, DC. 

Mucuna seeds of two kinds, not very dissimilar in appearance and 
evidently belonging to allied species, make up 6 per cent, of the larger 
drift cast up on the beaches of the Turks Islands. Of these about a 
third belong to M. urens, DC. and are not to be distinguished from 
seeds of the same species collected by me in the Pacific islands (Plant 
Dispersal, p. 80, etc.). The plant in flower and fruit, as observed 
by me in Jamaica and Tobago, corresponds to De Candolle's descrip- 
tion as given by Grisebach ; whilst seeds of the same species gathered 
by me on the Panama beaches were thus named at Kew. The seeds 
are semi-globose, nearly an inch across (20-24 mm.), and have a 
broad raphe, a fifth of an inch (5 mm.) wide, that nearly encircles the 
seed. They are typically greyish black or brownish black, but seeds 
in the drift may present a lighter hue. The other Mucuna seeds 
belong to a type often designated as " near urens " in this work. 
There are reasons for the belief that they are the seeds of M. altissima, 
DC, a species regarded as confined to the New World, and as such 
they are sometimes referred to in these pages ; but, as shown below, 
this identification requires confirmation. These seeds are twice as 
frequent as those of M. urens on the beaches of the Turks Islands. 
They are flatter or more depressed and are rather over an inch in 
diameter (26-30 mm.), and they possess a narrower but similarly 
encircling raphe (3-4 mm.). In colour they are usually a dark or a 
light brown, and when of the lighter hue they sometimes display 



FOREIGN DRIFT OF THE TURKS ISLANDS 121 



black mottlings. The distinctions, however, especially as regards 
the width of the raphe in the two species, sometimes disappear. 
One finds at times drift seeds that might be referred to either kind, 
and even the seeds of growing Jamaican plants of M. urens were 
not always constant in their characters. 

Bentham, when describing Mucuna altissima in the Flora Brasi- 
liensis (Mart. XV., part 1, p. 169, tab. 46, 1859-62), remarks that the 
fruit is unknown; but he figures with a query under this name a 
pod with seeds that are very like those designated " near urens " 
in these pages. Grisebach (1864) describes the legume and seeds of 
this species. The last are stated to be orbicular, compressed, eight to 
ten-tenths of an inch in diameter, and almost wholly surrounded by 
the raphe, a description, which, except for the smaller size, would 
apply to the drift seeds of the " near urens " type. The last are 
stated above to be rather over an inch across. The matter, how- 
ever, requires further investigation. 

Authorities are agreed that Mucuna urens is widely spread in the 
tropics of the Old and New World. In the latter it occurs in all the 
larger as well as in many of the smaller West Indian islands, and 
extends south to Peru and Brazil on the Pacific and Atlantic sea 
borders. There has been apparently some uncertainty about the 
limits of the species in the Old World, but there is no doubt that it 
is found in tropical West Africa as well as ^n the Pacific islands 
(Hawaii, Marquesas, Samoa) and in other regions. Mucuna altis- 
sima, to which the seeds of the other kind probably belong, is, accord- 
ing to Grisebach, a peculiar American species distributed over the 
West Indies and occurring on Central America and in Brazil. 

The same two kinds of Mucuna seeds also came under my notice 
frequently in the beach-drift of other parts of the West Indies besides 
the Turks Islands — namely, in Trinidad, Tobago, Grenada, and in 
Jamaica ; and in their association they are evidently very character- 
istic of West Indian drift. On the beaches of Tobago and Trinidad, 
where they are numerous and often encrusted with Balani, they occur 
in nearly equal numbers. As far as I could judge from the Morris 
collection of Jamaican beach-drift in the Kew Museum, the same two 
sorts of Mucuna seeds are there represented under the name of 
M. urens. As occurring in West Indian drift the seeds of both sorts 
are usually sound and germinable. They are those that are trans- 
ported across the Atlantic to Europe in the Gulf Stream drift. It 
may be here stated that Ridley, in 1887, found two seeds of Mucuna 
urens, D.C., stranded on Fernando Noronha, off the coast of Brazil 
(Journ. Linn. Soc, vol. 27). The plant grows on the mainland; 
but it is far more probable that the seeds were brought in the Main 
Equatorial Current from the Gulf of Guinea. 

Peculiar (as far as my experience goes) to the Trinidad and Tobago 
beach-drift are the seeds of another species of Mucuna readily recog- 
nised by their larger size (lj-lj inch, 31-37 mm.), by their flatter 
form, and by the great width of the encircling raphe (9 or 10 mm.). 
They are greyish or brownish black, usually sound, and to quite half 
of them the shells of marine organisms (annelids, cirripedes, etc.) 
are attached, an indication of a previous flotation of months in the 



122 PLANTS, SEEDS, AND CURRENTS 



sea. Since the drift always reaches these islands from the southward 
and eastward, it is likely that these seeds were brought by the 
Equatorial Current flowing northward along the coasts of Brazil, 
and it is not beyond the limits of possibility that they might even 
have been brought over from the African coasts. 

It is, however, with the two seeds of the " uteris " type (Mucuna 
urens and M. altissima ?) that we are here concerned. Singular 
confusion has arisen in the application of the specific name of 
pruriens DC. to one of these by older as well as recent botanists, 
a name which is really that of a very different species of Mucuna, 
a weed of cultivation and quite unsuited for distribution by the 
currents. The error seems to date far back, perhaps originating with 
the interpretation of a remark made by Forster, one of Cook's 
botanists; but the discussion of the matter is reserved for Note 10 
of the Appendix. Both of them came under my notice in a sound 
condition amongst the West Indian seeds stranded on the Azores. 
As in the beach-drift of the Turks Islands, those of the true urens 
type were only half as frequent as those of the other species. It is 
probable that the drift seeds of this genus which Darwin received 
with other drift from the Azores (Chall. Bot., IV., 291) belonged to 
these types. Evidently both kinds are often cast up on European 
beaches ; but it is noteworthy that of the five specimens from those 
beaches which I have handled — namely, from the South of England, 
Ireland, and the Shetland Islands, four belong to the " near urens " 
kind and one to the true urens type. However, both sorts are to be 
found amongst the West Indian drift seeds picked up in the South 
of England, as contained in the Kew collection. 

Ever since Sloane referred, more than two centuries ago, to the 
fact that these Mucuna seeds are frequently thrown up on the Orkney 
Islands, they have been frequently observed on European coasts, 
and they are often mentioned in this connection in Chapter II. On 
the Scandinavian beaches they are very commonly noticed according 
to Sernander (pp. 119, 143), and have even been found on the Baltic 
shores, being alluded to under the name of M. urens, L., DC. land- 
man, who is there quoted, mentions the seeds of yet another species 
of the genus which have been found on Scandinavian beaches. They 
are referred with a query to M. macroceratoides, DC. In the Index 
Kewensis, M. macroceratides is accredited to Brazil. It was evi- 
dently to M. urens that Lyngbye alluded when he identified some 
seeds picked up by him on the Faroe Islands in 1817 as belonging to 
Dolichos urentis, a matter already mentioned in Chapter II. 

The records of these seeds on European beaches are to be found 
scattered through Chapter II. In this place they are briefly given 
together. Next to the record of their occurrence in the Faroe Islands 
we have that for the Shetland Islands. The specimens sent to me 
from that group were of the " near urens " type. Mr. Peel refers 
to seeds probably of Mucuna urens as amongst the West Indian seeds 
thrown up on the outer Hebrides ; and it cannot be doubted that they 
frequently reach the west coasts of Scotland. On the Irish coast 
they are regular constituents of the West Indian drift there stranded. 
For my information relating to this locality I am mainly indebted 



FOREIGN DRIFT OF THE TURKS ISLANDS 123 



to Miss Knowles. The only Irish seed inspected by me came nearest 
to the true urens type. 

On the beaches of the South of England Mucuna seeds are occa- 
sionally found. In the Kew Museum there is a specimen named 
M. urens from Cornwall, and another specimen from the Isle of 
Wight is named u near M. wrews." I found a sound seed of the kind 
last mentioned on the south coast of Devonshire, and Hemsley names 
Mucuna seeds (doubtless of one or other of these two sorts) as picked 
up near Portsmouth (Chall. Bot., IV., 291). Many of these seeds found 
on European beaches are quite sound. Lindman procured the 
germination at Upsala of seeds of M. urens obtained from the Scan- 
dinavian beaches (Sernander, p. 7); and in this connection it is 
important to note that seeds gathered by me from the plant in the 
Hawaiian islands germinated and gave rise to healthy plants, after 
being kept afloat in sea-wa f er for a year (Plant Dispersal, p. 80). 

With regard to the buoyancy of the seeds of these two kinds of 
Mucuna, their frequent occurrence in beach-drift and their ability to 
cross the Atlantic unharmed are facts of observation above recorded. 
In my woik on Plant Dispersal (pp. 80, 81, 531, etc.) I deal more 
especially with the seeds of M. urens as found in the Pacific islands. 
Though, as above observed, seeds remained afloat after a year in sea- 
water and subsequently germinated, it was indicated in my experi- 
ments that on account of the liability of the seeds to absorb sea- water 
and swell in the warmer parts of the ocean, a large proportion, at 
least 50 per cent., would sink in the early part of the transatlantic 
passage. 

As concerns the station of the plants of Mucuna that are most 
frequently represented in West Indian beach- drift, I have only 
data for M. urens proper ; but doubtless the plants yielding the seeds 
of the other kind are similar in their habits. If, as is not unlikely, 
the last mentioned prove to be the seeds of M. altissima, DC, then 
we are concerned with a species that grows in mountain-woods in 
the West Indies and on the tropical American mainland. This 
species came under my notice as a tree- climber around the lake of 
the Grand Etang in Grenada, but not in seed. M. urens came under 
my notice in Jamaica climbing on the trees of the wooded slopes of 
the Black River above Lacovia, and also in the " pen " district 
around Moneague in the centre of the island, growing on trees by 
the side of ditches. I also found it hanging from the trees on the 
banks of Les Coteaux River in Tobago. In such stations the seeds 
are very likely to fall into streams and rivers, and they may be 
observed amongst the drift stranded at the mouths of rivers, as in 
the case of the Black River and of the White River in Jamaica. It 
is in this manner that the seeds of this plant are generally brought 
within the influence of the ocean currents, being first carried down 
by rivers from inland regions to the sea. 

However, not all the seeds of Mucuna urens that fall into the rivers 
reach the sea, since a number of them sink in fresh-water. I did 
not test the relative buoyancy in fresh-water of seeds gathered 
directly from the plant ; but the seeds of the beach-drift, though they 
all float in sea-water, not infrequently sink in fresh-water. Ten 



124 PLANTS, SEEDS, AND CURRENTS 



per cent, of the seeds of the Turks Islands beach-drift and 20 per cent, 
of the drift seeds of Trinidad and Tobago sank in fresh-water. It 
may be added that of the seeds of the allied species (near urens) 
found in the beach-drift of the two localities just named, all floated 
in sea-water, but 20 per cent, of those of the Turks Islands and 
9 per cent, of those of Trinidad and Tobago had no buoyancy in 
fresh-water. In their buoyant behaviour the seeds of these two 
kinds of Mucuna, so common in West Indian beach-drift, illustrate 
the fine adjustment, referred to on pages 96 and 181 of my work 
on Plant Dispersal, that is not infrequently to be observed with the 
seeds of leguminous plants dispersed by currents. This principle 
would probably be exemplified in a more marked manner by Mucuna 
seeds taken direct from the plant, just as has been already described 
in the case of Entada scandens. An obvious implication of the 
results of these experiments on the relative buoyancy of such seeds 
in salt and fresh water is that a good proportion of those found in 
beach-drift must have grown on coast trees, since they could not 
have been carried down to the sea from inland districts by a river. 

In this connection one may add that of the large Mucuna seeds 
of the Trinidad and Tobago beach-drift, which are described without 
a specific name on page 121, 50 per cent, sank in fresh- water, although 
all floated in the sea. 

Fevillea cordifolia, SW. (Antidote Vine) 

This plant belongs to a cucurbitaceous genus holding about six 
species, all of which are tropical American and West Indian. It is 
a climber on high trees, and where a river traverses a wooded region 
the fruits often fall into its stream. It has a wide distribution in 
the West Indies (Cuba, Jamaica, Hispaniola, Porto Rico, Guadeloupe, 
Martinique, Trinidad, etc.), and in tropical America. 

As in the case of Grias cauliflora (see p. 211) the discussion of its 
means of dispersal raises some critical questions relating to their 
connection with the area of distribution. Both are restricted to the 
tropics of the New World, and both display a general unfitness for 
dispersal by currents — an unfitness not concerned so much with 
deficiency in the floating power of the seed (Fevillea) or of the fruit 
(Grias) as with the loss of the germinative capacity. 

I will at first refer to the mode in which the seeds reach the coast in 
Jamaica, and then to their condition in the beach-drift, where they occur 
in numbers. The station of the plant as a vine on the trees bordering 
the Black River is noticed on page 15. The fruit is heavy, rounded, 
and four to five inches in diameter ; and since the plant often grows 
on the tree-branches spreading over the water the fruits frequently 
fall directly into the river. Only a few ripe fruits were to be seen 
on the plants when I examined the Black River in January 1907; 
but I learned from one of my boatmen, a native of the district, 
that the " ploom-ploom," as he termed it, of the fruits as they fall 
into the water is commonly to be heard when ascending the river 
in March. However, during my ascents I observed both fruits and 
seeds afloat in the drift, the last being very frequent. 



FOREIGN DRIFT OF THE TURKS ISLANDS 125 



The ripe fruit, which usually contains about ten seeds, floats 
when it falls into the water. In course of time it breaks down 
whilst still at the surface, the seeds escaping and floating away; 
its buoyancy being due not only to the seeds but also to the floating 
power of the pericarp. The seeds are flat and round and about 
two inches across. They are as buoyant in the moist fresh condition 
when just freed from the fruit as they are in the dry condition. 
The embryo which forms the kernel has no buoyancy, the seed 
owing its floating power to the coverings. On first examining it, 
the seed would seem to be structurally well equipped for transport 
by marine currents. In the moist fresh state, when the embryo or 
kernel fills its cavity, the cotyledons are closely appressed; but the 
embryo is imbedded in spongy cellular tissue, especially aeriferous in 
its outer part and very buoyant. Outside this tissue is a thin crus- 
taceous shell, which is non-buoyant, but the seed possesses an outer 
border or edging, 4 to 5 mm. thick, of a brownish suber-like material 
which is very buoyant. Thus it is that when, as often happens, an 
empty seed splits into two halves in the manner below described, the 
two portions float away and occur loose in the drift. In the older seeds 
found afloat in the river the inner spongy tissue is drier, brownish, 
and increased in buoyancy; whilst the floating power of the seed 
is sometimes augmented through an empty space in its interior due to 
the shrinkage of the embryo. 

But there is a weak place in the seed's structure as far as buoyancy 
is concerned, since water is apt to penetrate the suture between the 
two halves of the crustaceous shell. This might favour the germina- 
tion of a seed floating in a river; but it would be fatal to the ger- 
minative capacity of a seed floating in the sea. This explains the 
condition of the seeds found afloat in the Black River drift, many of 
which must have been a long while out of the influence of the current 
and doubtless belonged to the previous fruiting season. They were 
very frequent in the river-drift in January, and I examined a 
considerable number of them from my canoe, with the following 
results — 

Sound seeds (one or two germinating) 50 per cent. 
Seeds injured by boring animals or by 

the nibbling of fish . . . 15 ., ,, 
Seeds empty or with decaying embryo 30 ,, ,, 
Seeds represented by the two separated 

halves of the shell . . 5 „ 

100 

Thus, excellent as the provision for long flotation at first sight 
seems to be, it is really very faulty, and it is doubtful whether 
effectual over-sea transport is possible for any distance. 

Reference will now be made to the testimony of these seeds as 
they lie stranded on the Jamaican beaches after being brought 
down by the rivers. I especially studied their condition on the 
beaches stretching four or five miles on either side of the mouth of 



126 PLANTS, SEEDS, AND CURRENTS 



the Black River, where they occur in numbers, and obtained these 
results — 

Fresh-looking seeds with seemingly 

sound kernels . . . .10 per cent. 

Seeds with decaying kernels . . 20 ,, 

Empty seeds . . . . 45 „ ,, 

Seeds represented by the separate 

halves of the shell . . . 25 ,, ,, 

100 

By comparing the above results with those before given for the 
floating drift of the Black River, we see at a glance that the proportion 
with sound kernels or embryos has fallen from 50 to 10 per cent., 
which is by no means a promising sign of fitness for ocean transport. 

The seeds came also under my notice on the beaches of other 
parts of Jamaica, as at St. Anne's Bay and at the mouth of the 
White River, but with unsound kernels or merely as empty shells. 
It should be mentioned in this connection that Mr. Hemsley, speaking 
of the seeds gathered by Mr. Morris on the sea- shore off Kingston 
in the same island, says that they " look quite sound " (Chall. Bot., 
IV., 302). It may, however, be surmised that, as the seeds were 
collected for transmission to Kew, only the soundest specimens 
would have been selected. Only the empty seeds came under my 
notice on the Trinidad beaches, the plant according to Hart's list 
growing on the island. 

The next stage in the progress of the seeds in crossing the ocean 
would be presented in the stranded drift of one of the outlying 
groups of the West Indies, where the plant does not grow, as in the 
Turks Islands. To reach these islands the seeds would have to 
traverse usually some hundreds of miles of sea in their journey by 
the prevailing surface drift-currents from the islands to the eastward 
and southward. Now the following was the state in which these 
seeds presented themselves to me as they lay stranded on the beaches 
of the Turks Islands, and their testimony goes to emphasise their 
unfitness for ocean transport. 

1 Seeds with seemingly sound kernels 5 per cent. 
1 Seeds with kernels of doubtful 

soundness . . . . . 15 „ „ 
Seeds with decaying or decayed 

kernels . . . . . 30 ,, ,, 
Empty seeds. . . . . 30 ,, „ 
Seeds represented by the separated 

halves of the shell . . . 20 „ ,, 

100 

Similar indications were offered in the results of flotation experi- 
ments conducted in England during the summer on seeds that had 

1 It is extremely doubtful whether any of the seeds were germinable. 



FOREIGN DRIFT OF THE TURKS ISLANDS 127 



been taken from the ripe fruit in Jamaica five months before. Of 
four placed in fresh-water one sank in three weeks and displayed 
on examination a decaying kernel. One sank in seven weeks, and 
failed to germinate when placed under suitable conditions, the 
embryo proving to be in a putrid condition. Two remained afloat 
after two months, and of these one showed a kernel beginning 
to decay, whilst in the other it was quite fresh and sound. Of four 
put in sea-water at the same time, one sank in three weeks and 
another in six weeks, both losing their kernels by decay when sub- 
sequently placed in soil. Of two that floated after a couple of 
months immersion, one showed a putrid kernel and the other a kernel 
in an earlier stage of decay. 

The outcome of all these observations on the seeds of Fevillea 
cordifolia is that after they have been freed by the breaking down 
of the fruit floating in river- drift they will float for a long time un- 
harmed in the fresh-water, some of them ultimately germinating 
at the surface. Of the numbers that would not be detained in the 
river but would be carried down to the sea, most would soon succumb 
to the injurious effects of salt water, and probably none would 
preserve their germinative capacity after floating for several weeks 
in the sea. A scale of progressive deterioration is indicated by my 
observations, beginning with those seeds floating in river-drift 
where 50 per cent, are sound, then taking those stranded on the 
neighbouring sea-shore where 10 per cent, only are sound, and ending 
with some sandy islet a few hundred miles away, where only 5 per 
cent, would be regarded as sound. Seeds that behave in this fashion 
could never cross an ocean unharmed, though it is quite likely that 
the empty crustaceous shell, or its separated halves, would be found 
amongst the West Indian drift stranded on the coasts of Europe. 

Manicaria saccifera 

As it is a little doubtful whether one or more species are included 
under this name, it is here used in a general sense. The stranded 
fruits of these palms came under my notice in widely removed 
localities of the West Indies, as in Jamaica, Tobago, Trinidad, and 
the Turks Islands, and I may here add Colon. They have long been 
known as occurring in the beach-drift of Barbados and of other 
islands of the Lesser Antilles, and in recent years they have been 
noticed on the Cayman Islands. Yet with the exception of Trinidad, 
none of the West Indian islands are known to possess these palms. 
The observant Jamaican native when he picks up on the beach the 
" sea coco-nut," as he calls it, will tell you that it has been " brought 
by the waves from a distance." So also the Barbadians, who name 
it " sea-apple," can have no acquaintance with the palm. 

The distribution of these palms is very interesting. Though 
recorded from the estuaries of tropical South America, as from the 
Amazon, the rivers of the Guianas, and the Orinoco, Trinidad repre- 
sents its only known insular habitat. Yet the presence of the drift 
fruits in such numbers in the Turks Islands at the south-east ex- 
tremity of the Bahamas seems to indicate that the palms grow in 



128 PLANTS, SEEDS, AND CURRENTS 



the estuaries of the large islands to the southward and eastward, 
such as Hispaniola and Porto Rico. However, Urban up to recent 
times did not know of their existence in those two islands, since he 
refers to their fruits as brought from South America to Porto Rico 
by the currents (Symbolce Antillance, IV., 131, 1903-11). Writing 
about 1885 Hemsley remarked that it is quite possible that these 
palms exist in Jamaica (Chall. Bot., IV., 303) ; but Morris a few years 
later wrote that on account of their striking appearance and the 
peculiarity of their entire leaves these palms, if they existed in the 
island, " could not fail to be noticed " (Nature, January 31, 1889). 

Manicaria saccifera is essentially a palm of the Amazon estuary, 
its native name being Bussu or Ubussu. Spruce tells us that it 
abounds on both banks of the Lower Amazon (Notes of a Botanist, 
etc., I., 56). Martius, as quoted by Hemsley (Ibid.), writes that it 
is abundant on the banks of the Amazon estuaries, but is not known 
from the interior of the continent. Bates observed many of the 
fruits afloat in the sea about 400 miles off the mouth of the main 
estuary of the Amazon, mingled with much drift brought down by 
the river (The Naturalist on the River Amazons, 1864, p. 461). The 
Ubussu palm, as he also characterises it, is described by him as growing 
on land overflowed by the tide in the estuaries of that great river 
(Ibid., pp. 69, 139). These palms play the same role in the Lower 
Amazon that is taken by Nipa fruticans in the estuaries of tropical 
Asia and Malaya. 

According to Sloane's Natural History of Jamaica (II., 186) these 
fruits in his time (the close of the seventeenth century) were fre- 
quently cast up on the Jamaican beaches, and were amongst the 
West Indian drift thrown up by the " Currents and Seas " on " the 
north-west islands of Scotland." He refers to Petiver's description 
and figure in his Gazophylacium Naturce (tab. 64, fig. 3, p. 6), where 
it is mentioned as a fruit " from about Cartagena in America." 
Hemsley quotes Sloane in this connection (Chall. Bot., IV., 303), 
and reference for further particulars should be made to his pages. 

Doubtless the fruits of this palm have since been often found on 
European coasts, but seemingly they have rarely been identified. 
There is but little ground for believing that the drifting fruits ever 
retain the germinative capacity when stranded on the shores of 
Europe. I became very familiar with these drift fruits in various 
localities of the West Indies, widely removed from each other, and 
formed the conclusion that, as far as concerns the disposal of the 
species, the floating fruit would be quite ineffective except in the case 
of very short 'sea traverses. 

The fruit is one to three lobed, and has an outer almost woody 
warty or fuberculate covering, rudely suggestive of some coniferous 
fruit, a covering that is soon lost in the drift. Plukenet's description, 
as quoted by Hemsley (Ibid.), of the fruit cast up on the coasts of 
Barbados — fructum externo cortice denudatum — is true of the great 
majority of the stranded fruits on West Indian beaches, and would 
apply to all fruits stranded on the shores of Europe. But at times, 
as on Jamaican beaches, and on very rare occasions in the Turks 
Islands, one finds a fruit with its " cortex " more or less intact. 



FOREIGN DRIFT OF THE TURKS ISLANDS 129 



Plukenet states that Sloane showed him specimens obtained from 
Jamaica that retained this outer case. I find it difficult to believe that 
such fruits did not reach Jamaica from some source nearer than 
Trinidad and the Orinoco and Amazon regions. I only found the 
fruits retaining the " cortex " on the north side of the island, and it 
will be pointed out below that it is just on these northern Jamaican 
beaches that these drift fruits are most numerous and most likely 
to be at all fresh. The foreign drift on the north coast of Jamaica 
must be mainly Cuban and Haitian ; whilst that on the south coast 
would be largely brought by the Equatorial Current from Trinidad 
and the adjoining estuary of the Orinoco, as well as from the Amazon 
estuaries further south. 

On Trinidad, where these palms grow in the swamps, and on the 
neighbouring island of Tobago, the entire fruits are frequently found 
in the beach-drift, where they are mingled with others that have 
lost the outer coverings, and have in some cases come from a great 
distance, since not a few are incrusted with Balani and similar 
marine organisms. 

Within the common casing are usually two or three (at times 
only one) globular fruits of the size of a small apple and covered 
by a hard thin shell, which is somewhat brittle and more or less 
adherent to the indurated skin of the kernel. The albumen lines 
a large cavity, as in the coco-nut, and it is to this cavity that the 
fruit's buoyancy is entirely due. It is the bared globular fruit that 
is characteristic of beach-drift over much of the West Indian region. 
Very rarely does one come upon a fruit that is seemingly " germinable," 
and then, as a rule, only in the vicinity of its home. In Jamaica, where 
the fruits are more numerous on the northern than on the southern 
beaches (probably in the first case largely derived from Cuba or 
Haiti, and in the last case cast up by the Equatorial Current), it is 
very difficult to find a fruit that could be characterised as sound, 
and when one is found it is on the north coast. Around the districts 
of Black River and Savanna-la-mar, on the south-west coasts, all 
examined had mouldy or unhealthy kernels with embryos gone or 
in a decaying state. On the north coast, as around St. Anne's Bay 
and its vicinity, I found that about 20 per cent, were rotting inside, 
and about 60 per cent, displayed sour-smelling, mouldy kernels and 
decaying embryos. The remainder were fairly healthy, but the 
embryos were excessively shrunken, and the albumen was usually 
hard and dry ; but in a few cases the contents were fresh and relatively 
moist and the embryo was healthy, water still remaining in the 
seed cavity. 

It is noteworthy in this connection that the fruits collected by 
Morris amongst the beach-drift off Kingston on the south side of 
Jamaica were found at Kew to possess unsound seeds (Chall. Bot., 
IV., 303). This is the rule in Jamaica. On the other hand, in an 
island like Trinidad, where the palm is at home in the coast swamps, 
fresh fruits are frequent among the stranded drift, 50 per cent, of 
those observed by me being sound. However, some of these fresh 
fruits may be derived from a source near at hand, namely, the 
estuary of the Orinoco. In Tobago, only twenty miles distant from 

K 



130 PLANTS, SEEDS, AND CURRENTS 



Trinidad, the proportion of sound fruits in the beach-drift is nearly 
as large. This island is not known to possess the palm, and doubtless 
its drift fruits are principally derived from Trinidad and the neigh- 
bouring Venezuelan shores. In both islands we also find old dead 
drift fruits incrusted with Balani that probably hail from the Amazon. 

Of the Manicaria fruits brought by the currents to the beaches 
of the Turks Islands not more than 1 or 2 per cent, appeared to be 
" germinable." Out of some scores observed I only found one or 
two in their cases, all the rest being bared fruits, and possessing in 
almost all cases either a mouldy kernel with the embryo more or 
less removed by decay, or a hard and dry kernel with the embryo 
greatly shrivelled. The stranded fruits occurred on all the larger 
islands ; but they diminished in frequency towards the south, being 
most numerous on Grand Turk in the north, and least common 
on Greater Sand Cay in the extreme south, where, however, other 
kinds of foreign drift abound. The indications are that these 
Manicaria fruits often arrive at the Turk Islands from Hispaniola, 
eighty or ninety miles to the southward. 

On Grand Cayman, which lies in the track of the Main Equatorial 
Current between Cuba and the coast of Honduras, quantities of these 
Manicaria fruits are thrown up. Mr. Savage English in his paper 
on this island in the Kew Bulletin (1913) remarks that occasionally 
perfect fruits are found (such as have been already described in a 
previous page from other localities); but no "sea coco-nut" has 
ever been known to germinate on Grand Cayman, and " there is not 
a tree of it on the island." He attributes the loss of the germinative 
capacity to the long flotation in the sea involved in the transit from 
Trinidad and South America. In a few cases signs of arrested 
germination were observed when the fruits were opened. As indicative 
of the source of these fruits, it is stated that a drifting bottle from 
off Ceara, to the north-west of Cape St. Roque, was picked up on 
the Cayman Islands. 

On the whole it may be inferred that the floating fruits of Mani- 
caria saccifera, as far as the retention of the germinative capacity 
is concerned, possess, in spite of their great floating powers, but a 
very limited capacity for distributing the species over wide tracts 
of ocean, though able to traverse in an effective condition the narrow 
seas dividing the West Indian islands, straits that rarely exceed 
sixty miles across and have usually not half that breadth. 

DlOCLEA REFLEX A, Hook. f. 

This leguminous tree-climber, which in many respects, as in its 
distribution, station, habit, general seed-characters, and dispersal 
by currents, presents much the same features as Mucuna urens, 
ranges through the tropics of Asia, Africa, and America. From the 
data given by various botanical authorities, more especially by 
Urban, it is highly probable that all the larger West Indian islands, 
and most of the smaller mountainous islands, possess it. Thus, it 
is already known from Jamaica, Cuba, Porto Rico, Dominica, St. 
Vincent, Tobago, Grenada, and Trinidad. But judging from my 



FOREIGN DRIFT OF THE TURKS ISLANDS 131 



own experience, and bearing in mind Grisebach's remark that it 
is uncommon in Jamaica, it would appear that, widely distributed 
as it is over this region, it is rarely frequent. Mucuna urens seems 
to be three or four times as common, and this difference, as we shall 
see, is reflected in the story of the stranded drift. 

In the West Indies it climbs the lofty trees of the inland forests, 
and especially favours the river-bank and the lake-side in wooded 
districts, so that its seeds are likely to drop into inland waters and 
to be carried down to the sea. But it also grows amongst the trees 
lining estuaries, though it could not in this region be placed amongst 
the typical coastal plants. The locality in which I especially studied 
this species was on the forested slopes of the lake and effluent of 
the Grand Etang in Grenada at elevations of 1800-2000 feet above 
the sea. Doubtless it finds its station on the densely wooded banks 
of the great rivers of Venezuela, the Guianas, and tropical Brazil; 
but it is not easy to find direct references to its station in those 
regions. However, Bentham, ascribes to it a station in woods 
near rivers in the Amazon area, and mentions the Rio Negro in this 
connection (Flora Brasiliensis of Martius, vol. 15, part 1). In tropical 
West Africa it finds its home near the coast and at the riverside 
(Hooker's Niger Flora.) 

The seeds, though less frequent than those of Mucuna urens, 
were found by the writer to be characteristic of beach-drift in Jamaica, 
the Turks Islands, Grenada, Tobago, and Trinidad. They are 
included in the Morris collection of Jamaican beach-drift in the Kew 
Museum. Though those of Mucuna have often been recorded from 
the drift stranded on European beaches, I have found no reference 
to those of Dioclea reflexa. This is probably due in part to the cir- 
cumstance that they have often been regarded as Mucuna seeds, 
a confusion which is apparent in some of the older allusions to West 
Indian drift on European beaches, and an instance is given below. 
Except in size, the diameter being about an inch in both cases, the 
appearance of such Dioclea and Mucuna drift seeds is dissimilar. 
Whilst the two sorts of Mucuna seeds characteristic of European 
beach-drift are orbicular in form, dark-grey in hue, and have a black 
raphe nearly encircling them, the typical seed of Dioclea reflexa 
shows black mottling on a light-brown ground, is squarish on one 
side, and its raphe is limited to two-thirds of its circumference. 

That the seeds of Dioclea reflexa are to be included amongst West 
Indian drift stranded on European beaches, will be now established, 
but they are far less common than those of Mucuna. Probably 
at least ten Mucuna seeds are washed ashore for each Dioclea seed. 
Although the writer has not found one himself on this side of the 
Atlantic, a sound seed of D. reflexa stranded on the Shetland Islands 
was sent to him by Mr. J. Tulloch of Lerwick for his inspection. 
Then there is the curious circumstance that Dr. James Wallace, in 
his enlarged edition (1700) of his father's book on the Orkney Islands 
(1693), substitutes a figure of a seed of a Dioclea, most probably 
D. reflexa, for one of Mucuna given in the earlier edition, as though 
they represented the same seed. Since the seeds of this species 
of Dioclea are able to reach the Shetland Islands, it would seem highly 



132 PLANTS, SEEDS, AND CURRENTS 



probable that they are cast ashore on the Norwegian coasts; but 
the name is not included in the list of West Indian seeds and fruits 
given by Sernander in his account of the Atlantic drift thrown up 
on those shores. However, one may expect to find these drift 
seeds also in the temperate latitudes of the South Atlantic. Hemsley 
records Mr. Moseley's discovery of the seeds of Dioclea reflexa washed 
ashore on Tristan da Cunha (Chall. Bot., IV., 291). 

In my book on Seeds and Fruits (p. 103) allusion is made to the 
habit of this climber of growing on trees beside streams in the moun- 
tain forests of Grenada ; and it is there shown how small would be 
the percentage of seeds that would be fit for attempting the Atlantic 
traverse. On this ground alone we are thus prepared to expect 
that the seeds of this plant would not be so frequently observed 
among the West Indian seeds thrown ashore on European coasts 
as those of Mucuna. Judging from my results in the Turks Islands, 
a locality which represents an early stage in the drifting of the seed 
across the North Atlantic, the seeds of Dioclea reflexa are rather 
less frequent than those of Mucuna urens and much less common 
than those of the other species of Mucuna. In the drift of the Trini- 
dad and Tobago beaches all three seem to be of equal frequency. 
In the Turks Islands the seeds of Dioclea reflexa were generally 
distributed in the drift, but were most frequent in the southernmost 
island. It is interesting to note that of the seeds of this plant collected 
in the beach-drift of this small group, 10 per cent, sank in fresh-water 
though buoyant in sea-water. This may be compared with the 
results of a similar experiment on the seeds of the same plant in the 
beach-drift of Trinidad and Tobago. Here 30 per cent, sank in 
fresh- water, though floating in sea- water. 

No reference has been made to the occurrence of Dioclea reflexa 
on the Pacific side of tropical America, as I possess no data directly 
bearing on that point. However, its place is well supplied there 
by Dioclea guianensis (Benth.), an allied species mentioned by 
Seemann, under the synonym of D. panamensis, as growing by rivers 
on both sides of the Panama Isthmus (Bot. Voy. H.M.S. Herald, 
p. 109). This species is stated to be a native both of the Guianas 
and of Ecuador ; and it is not unlikely that numerous Dioclea seeds, 
which I found afloat in the drift of the Guayaquil estuary in Ecuador 
and stranded on the beaches near its mouth, belong to this plant. 

Doubtless there are several recorded facts illustrating the dis- 
tribution of the seeds of Dioclea reflexa by currents in the tropics 
of the Old World, but the following will be sufficient for the purpose. 
Many years ago they were identified at Kew from collections of drift 
seeds made by me on the beaches of Keeling Atoll in the Indian 
Ocean and on the coral islets of the Solomon Group in the Pacific, 
as well as from another collection of floating drift obtained by 
Moseley off the coast of New Guinea (Journ. Vic. Inst., London, 1889 ; 
Bot. Chall. Exped., IV., 291, 309, 311). 

But there is an allied species of Dioclea, D. violacea, Mart., which 
plays a similar role in the tropical Pacific. I was familiar with its 
seeds in Hawaii and Fiji, and frequent mention is made of them in 
my work on Plant Dispersal. They are commonly brought down by 



FOREIGN DRIFT OF THE TURKS ISLANDS 133 



the rivers and deposited on beaches in Fiji, and my experiments 
showed that they can float for a year and more unharmed in sea- 
water. There is, however, a difficulty connected with the distribution 
of this species. It seems from Hemsley's reference to it (Bot. Chall. 
Exped., IV., 291) to have been first described from Brazil. Yet if 
it is so widely distributed by currents in the Pacific, having been 
recorded from Hawaii, Fiji, Tahiti, etc., it is strange that it should 
only be confined to Brazil in the New World and that its seeds do 
not figure in West Indian beach-drift. 

Interesting as the genus Dioclea is to the student of distribution, 
it only repeats the problems displayed by two other genera of legumi- 
nous tree-climbers, Mucuna and Entada, all three of them holding 
species possessing seeds capable of wide dispersal by currents, species 
that range over the tropics of the globe, and all three of them con- 
taining species of more limited range that, certainly in Entada and 
probably also in the other two genera, are not adapted for this 
mode of dispersal. These three genera thus behave like other 
leguminous tropical genera, such as Canavalia, Guilandina, Sophora, 
etc., that hold littoral species, found round the tropical zone, plants 
possessing buoyant seeds known to be distributed by currents far 
and wide over the oceans; whilst they own other species restricted 
to smaller areas and not capable of dispersal by the currents. In 
neither case could the agency of the current be appealed to in explana- 
tion of the distribution of the genera round the tropics. It is only 
the species of the estuary and of the beach that offer in the buoyancy 
of their seeds the opportunity for the currents. Species that habitu- 
ally grow away from the sea-beach on the river-bank as a rule possess 
seeds that sink, a fact brought out in my book on Plant Dispersal. 
These inland species with their limited range largely make up the 
genus, the distribution of which around the world opens up very 
different issues. 

Sacoglottis amazonica, Mart. (Humiriacew) 

This is one of the most interesting of the West Indian drift fruits 
that have been found on European beaches. Though characteristic 
of West Indian beach-drift, this fruit can scarcely be said to 
belong to a West Indian plant, since the small tree to which it belongs 
has its home in the Amazon estuary, and is otherwise only known 
from the island of Trinidad, where it is of very rare occurrence. It 
is, however, highly probable that the tree will be found in the estuary 
of the Orinoco, if it has not already there been found. There is 
no other fruit or seed amongst the West Indian drift of European 
beaches, about which it may be assumed with such confidence that 
the original source was one of the great estuaries of the South 
American mainland between the Equator and the Gulf of Paria, 
most probably the Lower Amazon. 

The story of the mystery that long surrounded the parentage of 
these drift fruits was told in Nature many years ago (January 31, 
1889; November 21, 1895) by Mr. Morris (now Sir Daniel Morris). 
Although they had been known for two centuries and more, not only 



134 PLANTS, SEEDS, AND CURRENTS 



amongst the strange constituents of Jamaican beach-drift but in 
European collections of curious seeds and fruits found on our beaches, 
it was not until 1889 that the parent plant was discovered. The 
subject was re-opened when Morris recognised in a drift fruit picked 
up at Bigbury Bay, South Devon, by Mrs. Hubbard in 1887, the same 
fruit that he had gathered on Jamaican beaches in 1884. Several 
botanists aided in the inquiry, Hillier, Oliver, Stapf, Urban and others ; 
but the source was definitely established when Mr. Hart in 1889 
sent from Trinidad to Kew some drawings made by Dr. Crueger 
in 1861, both botanists that in turn filled the position of Superin- 
tendent of the Botanic Gardens of Trinidad. 

Much of what follows was written before the author became 
acquainted with the fact that Morris had made a comprehensive 
investigation of the subject. The present writer had also dug 
deeply into the older botanical literature ; but here also he has been 
largely forestalled. Almost all that is of importance to the student 
of distribution respecting Sacoglottis amazonica was told long ago 
by Morris. However, as my investigations have been quite indepen- 
dent, and also because my account helps to fill up some of the gaps 
in the earlier researches, more especially in the handling of the drift 
fruits over a large area of the West Indian region, I venture to give 
my results much as they were written out before the papers of Morris 
in Nature were consulted. 

It is singular that Mr. Hart first introduced me to the parent 
plants of these strange drift fruits, with which I had been previously 
familiar on the beaches of Jamaica and Colon. Within an hour 
of my landing at Port of Spain in Trinidad, in December 1908, I 
was in the Botanic Gardens talking to a stranger about my diffi- 
culties in finding the parent plants of some of the seeds and fruits 
in West Indian beach-drift. He took me into the Herbarium and 
showed me some specimens. The stranger was Mr. Hart and the 
specimens were those of Sacoglottis amazonica. From him I learned 
that the small tree, to which the fruits belonged, grew in the estuaries 
of the Orinoco and the Amazon, and that if I wished to see it in its 
home I ought to visit those regions, since it was very rarely to be 
found on the swampy coasts of Trinidad. 

These drift fruits are spread far and wide over the West Indian 
region. I found them on the beaches at Colon, in Jamaica, and on 
the Turks Islands, Tobago, and Trinidad. There are specimens in 
the Kew Museum from Barbados, and Morris refers to one found 
afloat off an island between Grenada and St. Vincent. As before 
noted they were found by Morris in 1884 on the south coast of Jamaica, 
and almost two centuries before, 1688-9, they were observed by 
Sloane during his residence on this island to be frequently cast up 
on its shores. 

Although, as far as I know, not recorded from any island in the 
West Indian region except Trinidad, the regular occurrence of its 
drift fruits on the beaches of the Turks Islands, at the south-eastern 
end of the Bahamas, renders it highly probable that the plant grows 
on the large islands to the southward and eastward, such as Porto 
Rico and San Domingo, since it is from that direction that much of 



FOREIGN DRIFT OF THE TURKS ISLANDS 135 



the foreign drift reaches this small group. It is a tree of the Amazon 
delta and of the Middle Amazon, growing in woods on the river- 
bank. It is accordingly something more than an estuarine tree, 
since it extends far up the great river and has been found at Teffe 
some distance above the confluences of the Negro and the Madeira 
with the main stream. The latest reference I have found to the 
distribution of this tree is that given by Stapf in Morris's paper of 
1895. We learn from the Index Kewensis that the genus holds 
about ten known species, of which nine are Brazilian and one is 
found in the Guianas. Probably Sacoglottis amazonica is the only 
species that is dispersed by the currents; and it is pointed out in 
Chapter IV. that the limitation of this tree to the New World appears 
to be entirely a question of the arrangement of the currents, which 
would readily transport the fruits in a sound and effective condition 
from tropical West Africa to Brazil, but not from the tropics of the 
New World to West Africa. 

Before dealing with these fruits from the standpoint of their 
fitness for dispersal by currents, I will observe that they were charac- 
terised by Morris as possessing " ideal qualities " as drift fruits, 
their great buoyancy being due, as he points out, to numerous closed 
cavities or resin-cysts. The typical drift fruit, as he explains, has 
lost the outer fleshy covering of the fresh fruit. He found that two 
of the normal five cells of the fruit were usually suppressed. His 
account is illustrated by excellent figures of the fruit. 

They presented themselves to me in West Indian beach-drift 
as oblong woody fruits, about two inches long, and usually two- 
seeded. After the detachment of the ripe fruit from the tree, the 
outer fleshy covering evidently dries up and forms a dark-brown 
skin, which is soon lost in the " wear-and-tear " of the drift, and is 
only to be observed with fruits that have not travelled very far from 
the parent plant. When stripped of the outer skin the drift fruit 
presents a remarkable appearance on account of the rounded 
" bulgings " on the surface, which correspond to the empty resin- 
cavities beneath. It is in this bared condition as light-coloured 
warty ligneous fruits that they generally occur in West Indian 
beach- drift, the outer dark skin, two or three millimetres in thickness, 
having been lost, as above stated, in the " wear-and-tear " of sea 
transport. The two seeds lie in the centre of the fruit. They 
occupy long cells two-thirds of the fruit's length, but appear to be 
perfectly protected against the penetration of sea-water. Any 
weak place in the equipment of the seeds for traversing an ocean 
unharmed would be expected rather in the inherent inability of 
the seed to retain its germinative capacity for a period sufficiently 
long than in any defect in the protection afforded by the fruit-case. 

It is only at the extreme south-east corner of the West Indian 
region, namely, in the islands of Trinidad and Tobago, that these 
drift fruits present themselves on the beaches in a more or less 
entire state, that is to say, with the outer skin in a more or less 
perfect condition. The bared state, as Morris points out, is the typical 
condition of the drift fruit. In Jamaica they are always bared, 
and the same may be said of those in the beach-drift of the Turks 



136 PLANTS, SEEDS, AND CURRENTS 



Islands. On the beaches of the south coast of Trinidad these fruits 
are amongst the commonest constituents of the drift, and the seeds 
are often fresh. On the south-eastern beaches of Tobago, where 
the fruits are common, about a third of them contained sound 
healthy seeds. Since the tree is very rare on Trinidad and does 
not grow on Tobago, it is obvious that the fruits so characteristic 
of their beaches belong to the drift of the Orinoco and the Amazon ; 
and it is not surprising that in islands nearest to the true home of 
the tree the drift fruits should sometimes retain their outer coverings, 
and that the seeds should be often fresh. In the drift of the Turks 
Islands only about a fifth possess healthy seeds; but in this small 
group the seeds do not seem to be able to retain their sound appearance 
for a long time in the drift. However, though usually in scanty 
numbers, these drift fruits are to be observed on every beach of 
the Turks Islands, where the foreign drift collects in any quantity, 
from Grand Turk to Greater Sand Cay, at the extreme ends of the 
group. 

These fruits float buoyantly for many months. Three fruits 
from the Tobago beach-drift were placed in sea-water two years 
after their collection, and all still floated buoyantly seven and a half 
months later. In two of them the seeds proved to be discoloured 
and seemingly dead. In the third they appeared to be fairly sound. 
From the results of this experiment as well as from the indications 
supplied by the condition of the seeds in the stranded fruits on West 
Indian beaches as above described, it would seem that although 
the fruits would be able to withstand the immersion of a year and 
a half, which would be involved in their transport to the coasts of 
Europe, the seeds would probably lose their germinative capacity 
after the first six months. The floating power is to be entirely 
ascribed to the numerous impervious round empty cavities (3 to 5 
mm. across) in the substance of the woody case and to the impermeable 
outer surface of the fruit, when deprived of its skin. Neither the 
substance of the fruit nor the seeds possess independent buoyancy. 

It is apparent that Morris formed a similar estimate of the unfitness 
of the seeds for reproducing the plant after a prolonged ocean 
traverse. Though impressed with the ideal qualities of the fruit, 
as far as buoyancy is concerned, he remarked that there is "no 
record that the seeds have germinated after long immersion in salt 
water, or that the plant has established itself in a new locality outside 
its present area." As regards the last point it may be observed that 
it would scarcely be possible to discover such a record in the case 
of any large West Indian island, not even for Jamaica. We could 
not expect any proof more valuable than that which is supplied by 
the very scanty representation of Sacoglottis amazonica on the south- 
east coast of Trinidad. 

From what has just been said we would expect to find the fruits 
of Sacoglottis amazonica on European beaches, though not with 
sound seeds; and reference has already been made to a specimen 
in the Kew Museum which was picked up in 1887 by Mrs. Hubbard 
on the Devonshire coast. But from data given by Sloane in his 
Natural History of Jamaica (II., 186) it is apparent that these fruits 



FOREIGN DRIFT OF THE TURKS ISLANDS 137 



have long been known as constituents of the West Indian drift 
brought by the Gulf Stream to the shores of Europe. Although 
the parent plant was not known to him, he was able to compare 
its fruit with the accounts given by Petiver and others. " This is 
frequently cast up " (thus Sloane writes) " on the shores of this island 
(Jamaica) by the waves, and is one of those fruits thrown on the north- 
west islands of Scotland by the seas." He quotes the description 
given in a work thus designated — J. B. Cat. Jam., p. 214, " Fructus 
exoticus cinereus, cum lineis et tuberculis duris." He also gives 
Petiver' s description of his drawing of the fruit in his Gazophylacium 
Naturae (tab. 71, p. 5), " Fructus Jam. ovalis foraminosus," and the 
same author's account of " a hard oval fruit, with seed-holes round 
its surface, found on the shores of Jamaica," etc. Petiver' s figure 
and description, which I found in the 1764 edition of his book (plate 
71, p. 7), leave no doubt as to the identity of the fruit mentioned 
by Sloane as commonly stranded on the north-west islands of Scot- 
land. Probably these fruits were often figured in the works of 
the early botanists. Thus one is figured and well described by 
Clusius (Exot. Libr., libr. II., cap. 19, p. 45 ; 1605) as sent to him by 
Jacobus Plateau, but nothing more is said of its source. 

In the remarks just made I have briefly given the results of my 
examination of the older literature relating to the strange drift 
fruits of Sacoglottis amazonica, both on West Indian and European 
beaches. Since they were written, I have enjoyed the privilege 
of reading the papers of Sir D. Morris, who, with the assistance of 
Mr. E. G. Baker, made a more extensive inquiry in this direction, 
though I am not clear whether either of them noticed Sloane' s re- 
cognition of these fruits as thrown up on the north-west islands of 
Scotland. My references to the older literature may now be supple- 
mented from these sources. The description and figure given by 
Clusius in his work of 1605 were reproduced by J. Bauhin in 1680 
in his Historia Plantarum (torn, i., libr. 3, cap. cxi., fig. 1). One of 
the earlier allusions to this drift fruit is that of Johannes Jonston, 
who described it in his Historia Naturalis de Arboribus et Fructibus 
(p. 102), a work published in 1662. It was mentioned by Sloane 
as early as 1696 in his Catalogus Plantarum (p. 214) ; and here one 
may find an explanation of a reference of his in the preceding para- 
graph, J. B. apparently indicating J. Bauhin. Its discovery by Mr. 
E. G. Baker in the Sloane Collection in the British Museum, under 
label No. 1656, was of much assistance to Sir D. Morris in clearing 
up the mystery surrounding the origin of these drift fruits. 



CHAPTER VII 



THE LARGER FOREIGN DRIFT OF THE TURKS ISLANDS (continued) 
GUILANDINA BONDUCELLA, L. 

Since this plant and its seeds are discussed at length in my books 
on Plant Dispersal and on Seeds and Fruits, it is only necessary to 
repeat here that the seeds are able to float for years unharmed in 
the sea and that they retain their germinative capacity after being 
stranded on the shores of Europe. For the last two centuries and 
more it has been known that the seeds of this plant are frequently 
cast up on European beaches. This subject is dealt with in Chapter 
II. ; but it may be here observed that the writer himself found a 
seed, apparently sound, in April 1909, on a beach near Salcombe in 
South Devon. For many years and in several parts of the tropical 
zone, he has been familiar with this littoral shrub. Here, however, 
his remarks will be chiefly restricted to the results of his observations 
in the West Indian region. 

As a coast plant it is generally distributed in the West Indies from 
Jamaica to Trinidad. It occurs as frequently on small as on large 
islands ; and noteworthy amongst the former are the Cayman Islands 
where it was found by Millspaugh (Plantce Utowance). In Jamaica 
it came under my notice on the borders of nearly every beach ex- 
amined on the north and south coasts. It also came under my 
observation on St. Croix, Grenada, the Turks Islands, etc., as well 
as on the Colombian coast near Cartagena. Its seeds form a regular 
constituent of West Indian beach-drift, and came especially under 
my notice in this jonnection in Jamaica and the Turks Islands. 

This plant was observed by me only on Grand Turk, the northern- 
most of the Turks Islands; yet its seeds occur in the drift of the 
other islands of this small group under circumstances indicating that 
they formed a part of the general drift brought to these islands from 
the southward and eastward. Though not very frequent, a circum- 
stance probably due to their often being covered over by the heaped- 
up larger drift materials, a few of the seeds came under my notice 
on all the Turks Islands where drift had accumulated in any 
quantity on the beaches. On Grand Turk it thrives in places away 
from the beach in dry, rocky situations, especially in the northern 
part; and it only came down to the coast in places where the usual 
inland vegetation reached the beach. Since the seeds are regularly 
brought to this small group from outside regions by the currents, 
the limited occurrence of the plant is remarkable. There is evidently 

138 



FOREIGN DRIFT OF THE TURKS ISLANDS 139 



some influence that inhibits the establishment of Guilandina bonducella 
as a littoral plant in these islands. As I found a few seedlings on 
the beaches of Grand Turk, it is apparent that the excluding cause 
comes into operation after this stage. It may be that goats and 
other animals browse on the young plants, since the soft prickles 
that grow on the stems and on the under surface of the foliage could 
offer no protection, though when they harden in the older plants 
such protection would be afforded. 

It is probable that the same cause which prevents this plant from 
assuming its characteristic littoral station on the Turks Islands has 
operated throughout the Bahamas, an archipelago to which this 
small group geographically belongs. I did not find it included in 
the manuscript of Britton's and Millspaugh's Flora of the Bahamas, 
its place in those islands being taken by the allied species, Guilandina 
bonduc, which grows in coastal thickets. Neither species was recorded 
by Lansing in his thorough examination of the Florida keys (west 
of Key West). It is also apparent that although the seeds must 
often be stranded on the Bermudian islands, where several West 
Indian shore plants have found a home, the plant has not succeeded 
in establishing itself there, since General Lefroy's remark that it 
has only once been found (Chall. Bot., II., 30, 129) would scarcely 
justify us in considering it a successful colonist. On account of its 
cosmopolitan distribution as a littoral plant in warm latitudes we 
are apt to infer that it could make its home everywhere; but the 
foregoing negative facts of its distribution will prevent us from 
forming such a conclusion. 

In my book on Plant Dispersal (p. 192) it is stated that almost 
without exception the seeds of littoral plants of C&salpinia bonducella 
(Guilandina bonducella) in Fiji floated both in sea-water and in fresh- 
water, whilst in Hawaii the seeds of the same species growing inland 
all sank. (On consulting my Fijian note-books I find that out of 
forty-seven seeds from three different coast localities all floated in 
fresh- water.) I made some additional observations on these two 
points in the West Indies, that is to say, on the relative buoyancy of 
the seeds in fresh and salt water, and on the influence of an inland 
station on the floating capacity. With regard to the first point it 
may here be said that out of sixty- eight seeds obtained from plants 
growing by the beach at Savanna-la-mar in Jamaica 75 per cent, 
floated in fresh-water and 84 per cent, in sea- water. Of eighty seeds 
from plants growing by the beach near St. George's in Grenada 
95 per cent, floated in fresh-water and 98 in sea-water. Out of 
fourteen seeds collected from the beach-drift near Seville in Jamaica 
all floated in sea- water, but only twelve or 86 per cent, in fresh- water. 
It is thus evident that in the West Indies not quite all of the seeds 
of littoral plants float in sea- water, and that of those that are buoyant 
in sea- water not quite all float in fresh- water. We should represent 
a rough average result if we said that of a hundred seeds of plants 
growing by the beach ninety float in sea-water and eighty in fresh- 
water. 

Concerning the effect of an inland station on the buoyancy of the 
seeds I found that of a hundred seeds gathered from plants growing 



140 PLANTS, SEEDS, AND CURRENTS 



half a mile from the beach in Grand Turk all floated in sea- water and 
fresh-water. It appears, then, that an inland station does not 
deprive the seeds of their buoyancy in the Turks Islands, though 
in the case of plants growing inland on the old lava-fields of Hawaii 
this effect was produced. 

There seems at one time to have been a trade in the seeds of 
G. bonducella and G. bonduc between the New and the Old World. 
Sloane makes the curious observation (Nat. Hist. Jam., II., 41) that 
those of the grey-seeded " Nicker " plant (G. bonducella) were much 
esteemed for their medicinal virtues by the Turks. Respecting those 
of the yellow- seeded " Nicker " plant (G. bonduc) of the West Indies 
he writes that " the seeds are brought very plentifully into Europe 
for making buttons " (Ibid.). 

I am indebted to Prof. Ewart for the record of the occurrence of 
two stranded seeds of Guilandina bonducella on the shores of South 
Australia. They were found by Miss M. O'Dowd in 1912. He 
considers that they may have been transported there from the 
Queensland coast. They, however, did not prove to be germinable. 
As far as the current connections are concerned, it seems to me 
more likely that if brought from a distance these seeds must have 
hailed originally from Tropical East Africa or Madagascar. In that 
case they would have been carried by the Agulhas Stream within 
the influence of the West Wind Drift Current, and then across the 
Indian Ocean to Australia. This source is distinctly indicated by 
the tracks of bottle-drift reaching the Great Australian Bight, a 
subject discussed in Chapter XIII. 

Hymen^a 

Amongst the characteristic fruits of the Turks Islands drift occur 
two kinds of ligneous indehiscent legumes, of which one kind was 
identified by Prof. Pax as the fruit of Hymencea courbaril, the West 
Indian Locust-tree, whilst the other he considered to belong to an 
allied species of the same genus. These drift pods often occur entire 
with sound seeds ; whilst at other times some or all of the seeds are 
decayed. 

Hymenaea courbaril is a tall tree found over much of the West 
Indies and on the Central and South American mainland from 
Panama to the Guianas. As concerning its insular distribution, the 
fact that it occurs in Cuba, Jamaica, Porto Rico, Antigua, Dominica, 
St. Lucia, Trinidad, etc., indicates its wide range. It grows both in 
inland plains and in river valleys. In Jamaica it flourishes in all 
parts of the island and especially up the valley of the Black River 
(Fruits, etc., of Jamaica, by E. J. Wortley, Kingston, 1906). The 
legumes of this tree, as they occur in the drift of the Turks Islands, 
are broad, flat, 5 or 6 inches long, and contain about six seeds 
in a dry fibrous pulp that fills the fruit cavity. The seeds possess 
no buoyancy, and could only be transported across tracts of sea by 
the floating pod, which seems stout enough (the thickness of the 
walls being 3 to 4 mm.) to withstand the wear-and-tear of a passage 
across the Atlantic, though it is doubtful whether it would retain 



FOREIGN DRIFT OF THE TURKS ISLANDS 141 



its buoyancy for the many months that would be occupied in the 
traverse. 

The other pods, which are about 4 inches long and roundish rather 
than flat in section, hold about four seeds, enclosed in a similar dry 
pulp, of which some float and others sink m sea-water. The remarks 
above made concerning the fitness for being transported across the 
ocean apply also to these fruits. As far as I know no Hymencea 
pods have been recorded amongst West Indian drift on European 
coasts. 

Carapa guiaxexsis, Aubl. 

Carapa as a littoral genus is linked with Rhizopkora not only in 
its present distribution but probably also in its past associations. 
Carapa, like Rhizopkora, with which it is often associated in coastal 
swamp regions, has only a few species, the first-named possessing 
only five or six and the last three or four. In both cases the genus 
is mainly of the Old World, lending a species to the American conti- 
nent which holds it in common with the African West Coast. In 
both genera, therefore, the presumption is that the origin is Asiatic. 

Many critical questions of great importance are raised when we 
come to discuss the distribution of these two genera, questions, I 
may add, that were ably put by S chimp er years ago in his study of 
the Indo-Malayan coast flora. Both, as already indicated, are littoral 
genera, frequenting in the case of Rhizopkora coastal and estuarine 
swamps exclusively, and in that of Carapa both the swamp and the 
dry beach. In both cases there are two species that divide the 
warm regions of the globe between them in the same peculiar fashion, 
one appropriating America and the West Coast of Africa, the other 
monopolising the rest of the tropical zone from the East Coast of 
Africa eastward to the Western Pacific. In the instance of Rhizo- 
phora there are not wanting localities where the Old World species 
(Rk. mucronata) and the New World species (Rh. mangle) meet, as 
in Fiji, a matter discussed at length in my work on Plant Dispersal. 
As far as I can ascertain the two species of Carapa that hold the 
Tropics between them never meet on common ground, C. guianensis 
making its home in the warm regions of the New World and on the 
tropical coasts of West Africa, and C. moluccensis ranging from 
the Zambesi eastward to distant Fiji. [There is no need to raise 
the question here whether C. moluccensis, Lam., is distinct from 
C. obovata, Bl., another Asiatic form, since the distribution is much 
the same, and the student of dispersal cannot distinguish between 
the seeds of the two forms (see Chall. Bot., IV., 290).] 

Carapa guianensis is one of the features in the estuarine vegetation 
of the large rivers of Brazil, the Guianas, and Venezuela, and occupies 
a similar station in the adjacent West Indian island of Trinidad. 
Its occurrence in the Orinoco estuary accounts for the presence of 
so many of its seeds amongst the Orinoco drift on the south coast 
of Trinidad. The tree is abundant in the Lower Amazon, as at 
Para, and Spruce speaks of it as " met with all the way up the 
Amazon " {Botanist on the Amazon, etc., edited by Wallace, 1908, 
I., 480). I have not found, however, any reference to its occurrence 



142 PLANTS, SEEDS, AND CURRENTS 



on the Pacific side of tropical America, and in that respect the com- 
parison with Rhizophora mangle is incomplete. 

With the two species of Carapa that between them cover the tropics 
of the globe the writer is familiar, having studied the trees together 
with their fruits and seeds in Fiji and in Trinidad, and having gathered 
their seeds from the floating river-drift and the stranded beach-drift 
of various parts of the world, as on the south coast of Java, in the 
Keeling Islands, in Fiji, and in the West Indies. Though it does 
not seem that Treub found stranded Carapa seeds on the beaches 
of the devastated island of Krakatau, when he visited it in 1886, 
nearly three years after the great eruption, those of C. moluccensis 
were observed by Penzig in 1897 ; and when Ernst and other botanists 
examined this locality in 1906 they found Carapa trees established. 
The species was referred by them to C. obovata ; but there can be 
little doubt that the trees grew from such stranded seeds as were 
previously observed by Penzig, the two forms not being distinguish- 
able by their seeds (vide Treub and Penzig in Annates du jardin 
botanique de Buitenzorg, 1888 and 1902, and Ernst's New Flora of 
Krakatau, 1908). 

Carapa seeds were frequently noticed by me in the floating drift 
of the Rewa estuary in Fiji, and often in a germinating condition. 
They must form a feature in the drift of the estuary of the Orinoco, 
since many more drift seeds are piled up on the southern coasts of 
Trinidad than could have been derived from the trees in the coast 
districts of that island. We cannot doubt that they are equally 
abundant in the floating drift of the Amazon and of the rivers of 
the Guianas. 

But the grave perils that threaten the floating and the stranded 
Carapa seeds lessen their effective value for oceanic dispersal. In 
the first place, there is the tendency to germinate when afloat in an 
estuary before the sea passage begins. Then there is the tendency 
to germinate prematurely after being stranded on the beach at the 
completion of a long sea traverse. This, I especially noticed, in the 
Keeling Islands, where after a drifting passage of at least 700 miles 
the seeds often sprouted on the beach, the protruding portions either 
falling a prey to the crabs or being withered up in the sun. Then 
there is the danger from the attack of boring molluscs and other 
marine creatures during the ocean passage. This presented itself as 
a very real risk in the case of seeds of Carapa moluccensis that I 
found stranded in the Keeling Islands and on the south coast of 
West Java. Here the empty cavity was often occupied by the tubes 
of the Teredo. As a result of these repressive influences Carapa 
moluccensis seems never to have been able to establish itself on the 
Keeling Islands. Yet it may be remarked that the tendency to rapid 
germination on the part of a stranded seed, whilst usually leading 
to fatal results on an exposed sandy beach, would be a direct advan- 
tage on the muddy shores of a mangrove-fringed coast, where the 
germinating seed could at once strike into the mud in the shade of 
the trees. 

With respect to the occurrence of the seeds of Carapa guianensis 
in the beach-drift of the West Indian region, the following remarks 



FOREIGN DRIFT OF THE TURKS ISLANDS 143 



may be made. They were included in the drift collection made by 
Morris on the south coast of Jamaica (Chall. Bot., IV., 299), but 
nothing is said as to their condition. As the plant is not known 
from this island, the seeds were probably brought by the Equatorial 
Current in its passage across the Caribbean Sea. The seeds often 
came under my notice on the beaches of Trinidad, where the tree 
is at home. On the south coast very few of them were in a sound, 
fresh condition, many of them showing evidence of prolonged flota- 
tion in the sea in the incrusting shells of cirripedes and of other 
marine organisms, whilst others had been probably brought down 
by the Orinoco, since they were in a germinating but dried-up con- 
dition. On the north coast, as at Grande Riviere, they were more or 
less fresh, and had evidently been recently brought down by the 
river. They were frequent on the east coast of Tobago, often 
incrusted by cirripedes ; but as far as I know the plant is not found 
in the island. In the Turks Islands they mostly came under my 
notice on the east side of Grand Turk, half of them being empty, 
whilst not more than one in ten possessed sound seeds. 

Of the four West Indian localities above mentioned which dis- 
played the fruits of Carapa guianensis in the beach-drift — namely, 
Jamaica, Trinidad, Tobago, and Turks Islands, only the second as 
far as I know owns the parent plant. But from the regular occur- 
rence of the seeds in the drift of the Turks Islands, where the tree 
certainly does not grow, it may be inferred that the species is at 
home in the islands to the southward and eastward (San Domingo, 
Porto Rico, etc.), from which the drift seems to be largely derived. 
According to the writings of Grisebach, Hemsley, Spruce, and 
Schimper, the tree grows on the mainland at the coasts and in the 
estuaries of Central America, Venezuela, the Guianas, and Brazil. 

The fact that Carapa guianensis also grows on the coast of Sene- 
gambia in West Africa raises the issue as to the seed's capacity of 
crossing the Atlantic in a germinable state. Although the seeds 
will evidently float for many months in the sea, from the indications 
above given it is doubtful whether they would retain their germina- 
tive powers for so long a period. The risks, as I have shown, are 
great and numerous. It is especially questionable whether the seeds 
would withstand a sea passage of more than two or three months, 
or, in other words, whether for the purpose of effective dispersal 
they are fit for much more than distribution by the currents over 
the islands of the Caribbean Sea. This would quite exclude the 
possibility of their being able to reach in a sound state the tropical 
coasts of West Africa from the New World by the Gulf Stream 
route, which even by the way of the Azores would occupy twelve 
months and more. But, as we have seen, Carapa is mainly an Old 
World genus, the New World being presumably the recipient rather 
than the distributor. In that event it is quite possible that the 
seeds could accomplish the much shorter ocean passage, occupying 
only three or four months, in the stream of the Main Equatorial 
Current from the Gulf of Guinea to the coast of Brazil, a subject 
discussed in Chapter III. The fact that seeds of Carapa moluccensis 
are often cast up in the fresh condition on the shores of Keeling 



144 PLANTS, SEEDS, AND CURRENTS 



Atoll, after a drifting voyage of at least 700 miles and a passage that 
would require at least seven or eight weeks, renders this route across 
the Atlantic possible for the seeds of Carapa guianensis. 

MAMMEA AMERICANA, L. 

This well-known West Indian tree belongs to a small genus which 
has a remarkable discontinuous distribution. It holds six known 
species, of which three are tropical American and three are peculiar 
to Madagascar (Index Kewensis). In belonging to a genus of this 
description Mammea americana resembles several other trees that 
are referred to in this work in connection with drift. These dis- 
continuous tropical genera have a great importance. 

According to Grisebach and Urban this tree, which is confined to 
the New World, ranges from Cuba and Jamaica to Brazil, and is 
widely distributed in the greater and smaller West Indian Islands. 
It grows in the lower mountain forests of Jamaica, the locality where 
I made its acquaintance, and it is as a West Indian forest tree that 
it finds its natural station (see also Harshberger's work, p. 688, 
concerning its station in the islands of St. Thomas and St. John). 

The large russet-coloured drupes, four to six inches across, con- 
tain usually two or three large " stones," each consisting of a fibro- 
ligneous endocarp encasing the seed. Inside the tough skin of the 
fruit is a firm fleshy pulp. The fresh " stones " have no buoyancy; 
but since the pericarp is buoyant, it is probable that the fruit would 
float at first, though not for long, as the soft coverings would soon 
decay. The " stones " evidently acquire their floating power when 
drying on the ground after being freed from the fruit, the buoyancy 
being due partly to the dried endocarp and partly to the unfilled 
space arising from the shrinking of the seed. Though edible in a 
general sense for man, the fruits are more appreciated by animals. 
In Jamaica, according to Sloane, wild swine feed upon them. When 
dried after removal from the fruit the " stones " have a rough, pitted 
exterior; but as they occur in the beach-drift, after undergoing the 
wear-and-tear of sea transport, their surface is usually smooth and 
marked by interlacing fibres which give them a peculiar appearance. 
In this condition the " stones " are generally two and a half to three 
inches long and ovoid in shape. 

I found the " stones " in the beach-drift on the north coast of 
Jamaica (as at St. Anne's), on the south-east coast of Tobago, on 
the south coast of Trinidad, and on the Turks Islands. In the 
group of islands last named they form a regular constituent of the 
beach-drift, and came under my notice wherever the drift had 
collected in any quantity, as on Grand Turk, Cotton Cay, Salt Cay, 
and Greater Sand Cay ; but I rarely observed more than two or three 
on each beach. In all the four West Indian localities above men- 
tioned, the " stones " of the beach-drift gave little promise of being 
effective agents in the dispersal of the species by currents. Usually 
in half the cases the seed had decayed away; whilst in the rest, 
though the seed appeared sound, its hard consistence and dead- 
looking aspect on section did not indicate the retention of the germin- 



FOREIGN DRIFT OF THE TURKS ISLANDS 145 



ative capacity. It is thus evident that the tree possesses but little 
fitness for effective trans-oceanic dispersal by currents; and it may 
be inferred that if the fruits, in the shape of the " stones," ever 
reached the shores of Europe, which is unlikely, they would either 
be empty or would contain decaying seeds. 

But we may go further and observe that it is more than doubtful 
whether the agency of the currents could be appealed to for an 
explanation of the distribution of this tree over a large part of the 
tropics of the New World. The reason of its representation in the 
drift is probably to be found in its station on the forested slopes 
of river valleys, from which the bared " stones " of the fruits could 
be swept down into the rivers during torrential rains. If at times 
they are carried by the sea currents in a sound state from one island 
to another, the coast would offer a most unsuitable station for the 
establishment of a typical tree of the inland forests. It is possible 
that man has aided in its dispersal, since the edible fruit is appre- 
ciated by natives; but the main factor is, I think, to be looked for 
in the past, when the area of its distribution had not been broken 
up in the great changes which have resulted in the detachment of 
the large West Indian islands from the South American mainland, 
a matter referred to on other pages of this work. 

In his account of the Cayman Islands, Mr. Savage English (Kew 
Bulletin, 1913) tells us that the fruits of this tree are occasionally 
thrown up on Grand Cayman "in a more or less eatable condition " ; 
and he thinks that the tree may ultimately be introduced by the 
currents. However, it is already included in the flora of the Cayman 
Islands (Urban, Symbolce A?itillance, IV., 412) ; and if brought from 
a distance the drift fruits in question doubtless came from the 
neighbouring shores of Cuba and Jamaica. 

Gourds and Calabashes of the genus Crescentia 

In my work on Plant Dispersal (p. 570) it is observed that gourds 
and calabashes of Cucurbitaceous plants are frequently brought 
down to the sea in tropical regions and are thus likely to be dis- 
persed by the currents. Floating in the estuaries and stranded 
on the beaches, the gourds of a Cucurbita came often under my 
notice in Fiji; and their suitability for dispersing the species was 
established in one case, where seeds from a fruit that had been 
floating for at least two months in sea-water germinated in a few 
days. 

Gourds, usually small in size, were frequently observed by the 
writer afloat in the drift of the estuary of the Guayas in Ecuador, 
as well as stranded on the neighbouring beaches. Some of them 
were cucurbitaceous; but others were the wild fruits of Crescentia 
cujete, the Calabash tree, which belongs to quite a different family, 
the Bignoniacece. It was not until some years afterwards that he 
recognised these Crescentia fruits amongst his Ecuadorian drift- 
collections, having in the interval become acquainted with the tree 
in the West Indies. However, although the writer was not aware 
of it, they had long before been identified as gourds of Crescentia 

L 



146 PLANTS, SEEDS, AND CURRENTS 



cujete in a collection of Ecuadorian drift fruits and seeds which he 
had sent on his return to England to the Kew Museum. 

Gourds of sorts have long been known to be thrown up on the 
coasts of Europe. They are usually referred to as belonging to 
Lagenaria vulgaris (Cucurbita lagenaria), the calabash gourd of the 
Old World, and were long ago familiar to Scandinavian naturalists 
amongst the foreign drift cast up on their shores. Sernander deals 
with this subject on p. 119 of his work on the Distribution-Biology 
of the Scandinavian Plant-World (Upsala, 1901), and Hemsley refers 
to it in his Report on the Botany of the Challenger Expedition 
(IV., 277). These gourds of the Norwegian beach-drift were first 
described by Tonning, a pupil of Linnaeus. Found by Strom and 
Gunnerus in the eighteenth century and by Lindman in recent 
times, they have been in all cases referred to Lagenaria vulgaris. 
According to Sernander, the gourds stranded on Scandinavian 
beaches are usually "worked" calabashes; but he alludes to one 
that was not carved in this fashion, which contained several seeds. 

It is highly probable, however, that some of the gourds and cala- 
bashes recorded from the Scandinavian beach-drift were fruits of 
Crescentia cujete which had been brought in the Gulf Stream drift 
from the West Indies. By all the authors they are placed amongst 
the Gulf Stream materials heaped up on those coasts and associated 
with tropical seeds, such as those of Entada scandens and Mucuna 
urens, which are recognised as commonly brought by the currents 
to the Scandinavian shores from the West Indies. It will be shown 
below that gourds and calabashes of the genus Crescentia are very 
typical of West Indian beach-drift. The reason why their real 
character has been overlooked in the case of those found in European 
beach-drift may be found in the circumstance that unless one is 
familiar with the fruits in their homes, it is necessary to break open 
the gourd to identify the genus, and the discoverer of such a stranded 
fruit on a beach in Europe would probably be loth to spoil his 
specimen. 

Crescentia includes five species all confined to the tropical regions 
of the New World. The most familiar species is C. cujete, the Cala- 
bash tree, which is distributed over the West Indies, and on the 
American mainland from Mexico to Brazil. One would be inclined 
to think that man in the past must have assisted in its distribution, 
since its gourds are extensively employed as water vessels ; but it is 
noteworthy that another species, C. cucurbitina, L., which is referred 
to below, has a range almost as wide, notwithstanding that its fruits 
seem to be of little use to man. The Calabash tree thrives in Bermuda 
with all the appearance of being indigenous ; but Rein had grounds 
for suspecting that it had been introduced, and accordingly Hemsley 
does not include it in the indigenous Bermudian flora (Chall. Bot., 
II., 9, 55). The gourds of this tree are those most usually found in 
West Indian beach-drift. However, another species of Crescentia, 
C. cucurbitina, as above named, is not infrequently represented in 
the drift of this region. The tree, according to Grisebach, is dis- 
tributed over the West Indies from Cuba and Jamaica to Trinidad, 
and reaches the Spanish Main in Venezuela. Urban, who employs 



FOREIGN DRIFT OF THE TURKS ISLANDS 147 



for this species the synonym, Enallagma cucurbitina (Baill.), adds 
Panama to the list of localities (Symb. Antill., IV., 567). 

Gourds of Crescentia, more especially of C. cujete and C. cucurbitina, 
characterised the beach-drift examined by me in Jamaica, Turks 
Islands, and Trinidad. These three localities are sufficiently removed 
from each other to justify the inference that Crescentia gourds are 
generally characteristic of West Indian beach-drift. Numbers of 
fruits both from the living plant and from the drift were examined 
by me, and all of them belonged to this genus; and the implication 
arises that the gourds and calabashes carried by the currents from 
the New World to the shores of Europe would be fruits of Crescentia. 
The mode in which these fruits get within the influence of the currents 
is well illustrated in the Black River district of Jamaica. Both the 
trees named grow there at the riverside above the mangrove forma- 
tion. Their fruits form regular constituents of the floating drift, 
and are carried down to the sea in numbers, many of them being 
subsequently cast up on the beaches in the vicinity of the estuary. 

The next matter to be dealt with concerns the station of these 
two species of Crescentia. The Calabash tree, C. cujete, occurs both 
wild and cultivated in Jamaica ; but the natives distinguish the wild 
trees at a glance by their smaller fruits and by other characters. 
Grisebach supplies no station for the species; but Hemsley after 
giving its general distribution states that it grows commonly in swampy 
and marshy places (Chall. Bot., II., 55). It was in such stations that 
I usually found the wild tree in Jamaica; but it also grows there in 
the open woods of the lower levels. It came under my notice most 
typically as a tree of the interior of the Great Morass of the Black 
River district in this island, where it is associated at the riverside 
amongst other trees with Grias cauliflora (Anchovy Pear tree). Both 
Grias cauliflora and the Calabash tree, in bearing flowers and fruits 
on their trunks, exhibit the same feature of " cauliflory." Sloane, 
writing of the Calabash tree in Jamaica near the close of the seven- 
teenth century, says that " it grows everywhere in the Savannas 
and woods of Jamaica and the Caribes " (II., 173) ; but he makes no 
reference to its being cultivated. Urban, speaking of its general 
station in the West Indies, states that it grows in woods and is also 
cultivated (Symb. Ant., IV., 567). That the tree can thrive in dry 
stations is illustrated in the Virgin Islands, where it is associated 
with Cactacece and other xerophilous plants (Harshberger's Phytogeog. 
N. Amer., p. 687). 

Crescentia cujete is readily propagated from shoots; and it is on 
its powers of vegetative reproduction that the Jamaican cultivator 
seems to rely, the seeds according to common report being useless 
for the purpose. The fleeting vitality of the seeds is pointed out 
below. Crescentia cucurbitina, the other species represented in West 
Indian beach and river drift, is the " Paki " of the Jamaican. It 
was observed by me as a tall tree growing on the banks of the Black 
River above the mangroves, and also in wet ground near the coast 
below the Roaring River Falls on the north side of the island. 
Grisebach gives its station in Jamaica as the dry rocky coast. This 
is rather puzzling, since it is essentially a tree that favours moist 



148 PLANTS, SEEDS, AND CURRENTS 



localities. Urban, alluding to its station in the West Indies (Ibid., 
IV., 567), states that it grows in marshy places, both inland and 
at the coast. 

The suitability of the fruits of these two trees for dispersal by 
currents was especially studied during a sojourn at Black River in 
Jamaica. That they could be thus transported across wide tracts 
of sea soon became evident, and the point to be determined was 
whether after being stranded on some distant shore they were likely 
to contain germinable seeds. 

The fresh gourd of Crescentia cujete is filled with a white spongy 
pulp containing numerous seeds. After detachment of the fruit the 
pulp soon begins to soften and blacken; and a process almost of 
liquefaction sets in, which seems usually to involve the vitality of 
the embryos of the inclosed seeds, unless conditions favouring rapid 
germination intervene. As the fruit dries on the ground, its contents 
ultimately dry up, and all that represents the original white pulp and 
its seeds is a loose, rounded, blackened mass, about one and a half 
inches across, in which the seeds may be observed either empty or 
with embryos evidently dead, if not actually decaying. This is the 
condition in which the fruits of the Calabash tree generally are 
found in the Jamaican beach-drift, and anything less likely to 
assist dispersal by currents, as far as the propagation of the species 
is concerned, could scarcely be imagined. In these gourds of the 
shore-drift, when the embryos of the seeds have not disappeared, 
they are usually blackened, friable, and dead; whilst only in a few 
cases are there any signs of vitality; and even then the discoloured 
appearance and general condition give but little promise of any 
capacity for germination. 

The gourds of Crescentia cujete, as found in the beach-drift of the 
Black River district, were generally small, three to four inches across, 
globose, much weathered by exposure, and in half of them the shell was 
cracked. They were evidently derived from the trees growing wild 
in the Great Morass by the riverside, and had been washed up on the 
beaches after having been carried down to the sea. They came 
under my notice on the beaches near the mouths of rivers in other 
parts of Jamaica, as near the White River on the north coast. On 
the beaches of the Black River district they were four times as 
frequent as those of the Paki tree (C. cucurbitina). Their shells also 
are thicker (2 mm. as against 1 mm.), and the fruits generally seem 
better fitted for withstanding the buffeting involved in sea transport. 

The fresh gourds of Crescentia cujete float in water, and in this 
state they are not uncommon in the floating drift of the Black River ; 
but their buoyancy is principally due to the spongy air-bearing pulp 
and to the impermeability of the shell, the specific gravity of the 
last being near that of fresh-water. The fruit acquires increased 
buoyancy after the pulpy contents have broken down and dried 
up into a small rounded mass, leaving the greater portion of its 
cavity empty, such being its condition in the beach-drift. The fresh 
moist seeds, 9 or 10 mm. long, have an initial buoyancy, a capacity 
which they owe entirely to the fact that the embryo but loosely 
fills the cavity within its horny coverings. When dry they at the 



FOREIGN DRIFT OF THE TURKS ISLANDS 149 



most float for only a day or two. Under any circumstances, how- 
ever, the seed with its transient vitality, is quite negligible as an 
independent agent in current-dispersal. 

The fruit of the Paki (C. cucurbitina), which displays on its surface 
numerous pin-point pits, is ovoid or oblong, three to four inches long, 
with a blunt terminal point, its cavity being filled with a white, spongy 
pulp containing numerous non-buoyant seeds, 16 or 17 mm. across, 
and thus much larger than those of the Calabash tree (C. cujete). 
The seed contains a reddish embryo within a loose, white, mem- 
branous, sac-like covering; but as compared with the seeds of the 
Calabash tree those of the Paki are poorly protected, shrink greatly 
on drying, and are still more perishable in their nature. The fresh 
fruit floats, and was not uncommon in the drift of the Black River. 
As with the gourd of the Calabash tree its buoyancy is due to the 
air-bearing pulp and to the waterproof shell. Here also the pulp 
of the mature fruit soon undergoes a softening and blackening 
process; and here again the pulp and seeds ultimately dry up and 
cake into a loose, blackened, rounded mass occupying but little 
space in the fruit cavity, the seeds being dead and their embryos 
blackened and often friable. The Paki gourds thus appear to be 
even less fitted for the distribution of the tree through the agency 
of the currents than those of the other species. But apart from the 
condition of the seeds the gourd itself is less able to withstand the 
" wear-and-tear " of oceanic dispersal, since the shell is thinner 
(1 mm.) and more brittle than that of the fruit of the Calabash tree. 
The fruits are also less frequent in the beach-drift of the Black River 
coast than those of C. cujete. Their form, their pin-hole pits, and 
their blunt terminal point, as well as their large seeds, readily dis- 
tinguish them from the other gourds in the drift. They are described 
by Miers in the Transactions of the Linnean Society, Vol. XXVI., 1870. 

In the Turks Islands I found these two gourds to be regular con- 
stituents of the larger foreign drift of the beaches, as on Grand 
Turk, Cotton Cay, Greater Sand Cay, etc. Those of the Calabash 
tree were rather more frequent than those of C. cucurbitina in the 
proportion of three to two. Most of the former were the smaller 
fruits of the wild tree; but I also found one or two large calabashes 
six or seven inches across, doubtless the fruit of the cultivated tree. 
With both species the stranded gourds were much weathered and often 
cracked ; and all that were examined contained the usual dried-up, 
blackened, loose mass of pulp and dead seeds. A good proportion, 
however, had entire shells (perhaps half of them), and could have 
continued their ocean traverse. 

Since the plants do not grow in the Turks Islands, which derive 
their foreign beach-drift from the islands to the southward and 
eastward, we have here the completion of the first stage in crossing 
the Atlantic. It is highly probable that some of these floating 
gourds, more especially those of C. cujete, are included at times 
amongst the West Indian drift stranded on the shores of Europe. 
But their seeds would be always dead ; and it could be only in local 
distribution, as in inter-island dispersal, that currents could aid in 
the spread of the species. The occasional presence of a solitary 



150 PLANTS, SEEDS, AND CURRENTS 



wild specimen of the Calabash tree amongst the vegetation bordering 
the beaches on the Black River coast may be thus explained, the 
parent gourd having been brought down by the river. My Jamaican 
companions at once recognised them as wild, self-sown trees. 

Andira inermis, Kth. (Angeleen tree) 

This tree belongs to a genus of the Leguminosce, comprising about 
twenty species, all of which are confined to the tropical regions of 
the New World, with the exception of this species, which, according 
to Grisebach, Oliver, and others, also occurs in Senegambia on the 
West Coast of Africa. We learn from Grisebach that the Angeleen 
tree is distributed over the greater part of the West Indies from 
Cuba and Jamaica to Trinidad, and that it extends from Mexico 
along the Spanish Main to Guiana. 

Generally speaking it is a tree of the lower forests, but with a de- 
cided inclination, determined by the buoyancy of its fruits, to gather 
at the riverside. This preference for a station along the river banks 
is remarked by Grisebach for the tree in Jamaica ; and it was in such 
localities that I observed it in that island. The places in which it 
was more particularly studied by me in Jamaica were along the 
banks of the Black River above the mangroves, extending to the 
foothills of the central range, and in the hilly country at the back 
of St. Anne's. Its station by the riverside is the only fact connected 
with its range that can be brought into relation with its occurrence 
on the West Coast of Africa ; but this does not carry us very far. 
Although the river could bring the fruits within the influence of the 
ocean currents, there seems to be but little chance of their ever 
being stranded on the African coast with their seeds in a germinable 
condition. Since the genus is American, the New World must 
have supplied the opposite coast of Africa with this American tree ; 
and that could only happen now along the circuitous Gulf Stream 
route. That a pod stranded on the eastern shores of the Atlantic 
could contain a germinable seed, will appear from the following 
discussion to be most improbable. 

The fruit is a leguminous, indehiscent, one-seeded pod, about one and 
a half inches long, ovoid-globose in form, with (in the dry state) a loose- 
textured, fibro-ligneous husk 2*5 to 3 mm. thick. In the fresh con- 
dition, when it is moist and semi-fleshy, it has but little buoyancy, 
either sinking at once or floating only for a day or two; and thus 
the pods form no feature in the Black River drift, though the tree 
commonly grows on the banks with its branches overhanging the 
stream. In the dry state they are evidently much more buoyant; 
but the indications of my observations are that except in inter- 
island dispersal in the West Indian region the fruits would rarely 
contain a germinable seed when distributed by the currents. The 
stranded pods did not come under my notice in the Jamaican beach- 
drift ; but I gathered them in small numbers from amongst the foreign 
drift thrown up on the beaches of different islands of the Turks 
Group. Such drift fruits sometimes contained a seed; but it was 
hard, discoloured, and evidently unfit for germination. Since the 



FOREIGN DRIFT OF THE TURKS ISLANDS 151 



seed had no buoyancy, the pod must have owed its floating power 
to the light, loose-textured husk. There is little to show that the 
dry fruit would remain watertight for any length of time when 
immersed in sea- water. The only protection the seed itself possesses 
against the influence of sea- water is a thin permeable skin; and I 
think that the death of the seed of the floating fruit would soon be 
brought about through this cause. The pods probably reached the 
Turks Islands after a week or two's drift from the neighbouring 
coasts of San Domingo. 

For the reasons just given it would seem futile to look to the currents 
for the explanation of the existence of this tree on both sides of the 
tropical Atlantic. We have seen that since the West African region 
must have borrowed this species from the New World, we are debarred 
from appealing to the agency of the Equatorial Current in transport- 
ing seeds and fruits from the Gulf of Guinea to the American conti- 
nent. There remain only the possibilities of its reaching West Africa 
by the westward extension of the Guinea Current or with the Gulf 
Stream drift after it has crossed the North Atlantic. As shown in 
Chapter III., the first route receives but scant support from the 
evidence of bottle-drift, and the time required (at least six months) 
would negative its practicability for the effective dispersal of this 
tree. The objections would be still greater if we appealed to the 
second route, which would involve an ocean passage of about two 
years. In addition it is most unlikely, if plants like Saco glottis 
amazonica and Hippomane mancinella, which are so much better 
fitted for the Atlantic traverse, have failed to get away from America, 
that a plant with the limited fitness for dispersal by currents 
possessed by Andira inermis should be able to do so. 

Thus the currents fail to account for the occurrence of this tree 
on the coast of West Africa. But it is just possible that the light, 
empty pod might occur at times amongst European beach- drift, as 
it would probably continue to float long after it had ceased to be 
watertight. The great difficulty lies with the ill-protected seed. 
Under natural circumstances its germinative capacity would soon 
be lost, since the thin coats offer no protection against excessive 
shrinkage, and it would seem likely that ordinary air-drying would 
soon deprive it of vitality. 

Birds also fail us, since only a fruit-pigeon could carry such a 
large fruit, and that would only be possible between neighbouring 
islands or between adjacent insular and continental coasts. The 
difficulties here raised resemble in some points those presented in 
the case of the fruits of Chrysobalanus icaco, a plant also found on 
both sides of the tropical Atlantic (see p. 193). But there is this 
important difference in station. With the species of Chrysobalanus 
the tree is essentially littoral, and thus the currents when carrying 
the fruits to a distant coast would be bearing them to a suitable 
station. With Andira inermis, however, the stranded fruits would 
lie in most uncongenial conditions, conditions very different from 
those which the tree favours in inland districts, as in the humid 
forests of Porto Rico (Harshberger, pp. 685, 688) or by the riverside 
in Jamaica. 



152 PLANTS, SEEDS, AND CURRENTS 



Cassia fistula, L., and Cassia grandis, L. 

The pods of these two trees, which are often two feet long in the 
entire state, are characteristic of the foreign drift on the beaches of 
the Turks Islands, though in a fragmentary condition. I found 
them on the beaches of all the larger cays, such as Grand Turk, 
Cotton Cay, Salt Cay, and Greater Sand Cay. Portions of the same 
two fruits also came under my notice amongst the beach-drift of 
Trinidad and Tobago. The association of the pods of these two 
trees in the beach-drift of the West Indian region in localities so far 
removed from each other is worthy of remark. Those of Cassia 
fistula were also recorded by Morris from the stranded drift in 
Jamaica (Chall. Bot., IV., 301). We must therefore regard these 
singular fruits as regular constituents of West Indian beach-drift. 
Their occurrence in this connection on the Turks Islands is specially 
interesting, since the trees do not grow in those islands, and the pods 
could only have been brought by the currents from the large islands 
to the southward and eastward. On these beaches the pods of 
Cassia grandis are more frequent than those of C. fistula. 

Since Nature associates these two trees in the drift, we will deal 
with them together. Cassia grandis is indigenous in tropical 
America and in the larger West Indian islands (Grisebach). It is 
one of the several species of the genus that represent the remains of 
the original Antillean flora of the great Caribbean land-mass now in 
large part beneath the sea (Harshberger, Phytogr. N. Amer., p. 307). 
But Cassia fistula is usually regarded as introduced to America from 
its home in the Old World, although the matter is still one for dis- 
cussion. However, from the facts given by Sloane, to be subse- 
quently noticed, there seems little room for doubt that with Cassia 
fistula in the West Indies we are concerned with an introduced tree. 
De Candolle held with Sloane that it was brought by the Spaniards 
to America (Geogr. Bot., p. 772) ; and both Bentham and Grisebach 
regarded it as naturalised in the tropics of the New World. A good 
deal of interest attaches itself to this point, since the pods of Cassia 
fistula are amongst those found on the coasts of Europe with other 
West Indian drift. 

But before proceeding further in this discussion I will refer to the 
condition of the fruits of these two trees as presented on the Turks 
Islands beaches. The seeds, it should be remarked, have no buoyancy, 
being transported in the compartments of the buoyant pod ; but the 
long fruits break up in time in the floating drift, and though sea-water 
then penetrates some of the compartments, the fragments still float, 
being kept up by the air confined in the other chambers and by the 
buoyancy of the tissues forming the fruit. It is in this fragmentary 
state that these pods usually occur in the Turks Islands beach-drift, 
and also in that of other West Indian islands, the portions varying 
from four to ten inches in length and being as a rule much " weathered. " 
The smooth pods of Cassia fistula are, however, much better fitted 
for ocean transport than those of C. grandis, which have a rougher 
exterior and possess two lateral ribs that are very apt to be torn 
away in the drift, thus exposing the seed-chambers along more or 



FOREIGN DRIFT OF THE TURKS ISLANDS 153 



less of the fruit's length. Yet most of the seeds are too large to fall 
out of the pod at first; but the waves would soon complete the 
process of destruction, and the floating pod, with long rents in its 
sides, would probably not survive more than a month or two's 
buffeting in the currents. Only the pods of C. -fistula would be able 
to withstand the " wear-and-tear " involved in the passage across 
the Atlantic to the shores of Europe. It is, therefore, at first sight 
not surprising that they alone have been found stranded on European 
beaches. 

But before dealing with this matter, I will refer to the condition of 
the seeds in the fruits thrown up on the beaches of the Turks Islands, 
which represent the end of an early stage in the transatlantic 
voyage. Most of the seeds of these two species of Cassia are im- 
permeable to water, and they would withstand for a long time the 
effects of the penetration of sea- water into the floating fruit, which 
takes place sooner or later when the long pods, as generally happens, 
break in two. Those that are permeable would quickly swell up and 
lose their germinative capacities; whilst in time a number of the 
impermeable seeds would be also unable to retain their impervious 
character under the warm, moist conditions of the drift in tropical 
seas, and they, too, would swell up and become useless for propagat- 
ing purposes. But a good proportion of the seeds would be able for 
long periods to resist the penetration of sea- water, and transported 
in the floating fragments of the pod they would retain their sound 
state when stranded on some distant coast. Of the seeds found in 
the fragments of the pods of C. fistula and C. grandis on the beaches 
of the Turks Islands, between 20 and 40 per cent, were generally 
hard, entire, and quite sound on section; the rest had lost their 
germinative powers, having swelled up after the sea-water had 
penetrated the drifting fruit. 

The fragments of the pods of these two trees that are stranded on 
the Turks Islands could at the most have only drifted a few hundred 
miles, and seeing that more than half of their seeds have been killed 
by the penetration of sea-water, it seems unlikely that many sound 
seeds would be found in the pods of Cassia fistula that have been 
picked up on European beaches. I am assuming here that such 
fruits hail from the New World, which at first appears reasonable, 
since they are associated in the European beach-drift with seeds of 
Entada, Guilandina, Mucuna, etc., that undoubtedly come from the 
American side of the Atlantic. 

It would seem, however, that the records of the stranding of the 
fruits of C. fistula on the European side are not numerous. Accord- 
ing to Sernander (p. 117) they were found on the Norwegian coasts 
by Strom and Gunnerus, who flourished about the middle of the 
eighteenth century. Lindman in recent years has confirmed the 
identification of the species (Sernander, Ibid.). In this matter 
Hemsley (Chall. Bot., IV., 277) quotes Tonning, a pupil of Linnaeus, 
through whom the observations of Strom and Gunnerus, as Sernander 
points out (p. 116), are usually known in the scientific world. 
Nothing, however, is said by Sernander as to the condition of the 
pods and of the seeds when gathered on the Scandinavian beaches. 



154 PLANTS, SEEDS, AND CURRENTS 



Much depends on these points, since fruits that were entire and 
showed but little signs of* long exposure to the sea could scarcely 
have accomplished the passage from the New World. 

It is interesting to note the fact referred to by Hemsley (Chall. 
Bot., IV., 278, 301) that Martins raised plants from seeds of Cassia 
fistula cast ashore in the pod at Montpellier in the south of France. 
Hemsley cites this case as one of the instances where plants have 
been raised in Europe from seeds that have traversed the Atlantic. 
On this view the pod must have been carried through the Straits of 
Gibraltar into the Mediterranean after its ocean traverse. Here, 
again, much would depend on the condition of the stranded fruit 
when determining its probable source. It would seem safer, indeed, 
to look for a source much nearer home than the American side of the 
Atlantic ; for instance, in Egypt, where the tree has long been widely 
spread, since such pods might have been brought down to the sea in 
the Nile drift. At all events, the observations of Martins at Mont- 
pellier and of myself in the Turks Islands indicate that the pods of 
Cassia fistula can carry sound seeds across considerable tracts of 
sea; but the data at my disposal, whilst indicating the possibility 
that the pods can be transported from the New World to the shores 
of Europe by the currents, leave the question as to the condition of 
the seeds unanswered. There is a lack of information concerning 
the actual facts recorded, and for this reason a suspension of judgment 
may be necessary. 

It should be remarked that whilst the pods of Cassia fistula are 
characteristic of West Indian beach-drift, there seems to be but 
little mention of their occurrence in the drift of tropical beaches in 
the Old World. Let us take, for instance, the Indian Archipelago 
in its most comprehensive sense as including the whole region between 
south-eastern Asia and Australia. This region is regarded as one of 
the principal homes of the tree, and yet its fruits seem rarely to have 
attracted the notice of observers of the drift. Thus they are not 
named in Gaudichaud's description of the drift of the Molucca Sea 
as quoted by Hemsley {Chall. Bot., IV., 279). Schimper does not 
mention them in his account of the drift of the Java Sea and of the 
coasts of Java (p. 160). In my own paper on the drift of Keeling 
Atoll and of the south coast of Java no reference is made to them; 
and the same remark applies to the writings of Treub, Penzig, and 
Ernst on the new Krakatau vegetation, and to Moseley's account of 
the drift observed by the Challenger Expedition off the coast of New 
Guinea, as given by Hemsley (Ibid., IV., 285). It is possible that 
such fruits may have been at times regarded in the same light as 
the empty mango stones so frequent in tropical beach-drift, but this 
seems hardly likely. 

The divergence in opinion relating to the claim of Cassia fistula to 
be ranked as an indigenous American tree is illustrated by Hemsley. 
Whilst in one place he includes it amongst those plants certainly or 
probably dispersed by currents, in another place, when dealing with 
Jamaican beach-drift, he writes that it doubtless owes its present 
wide area to man rather than to any other agency (Chall. Bot., I., 43 ; 
IV., 301). It is odd that its pods are a feature of tropical beach-drift 



FOREIGN DRIFT OF THE TURKS ISLANDS 155 



in the New World rather than in the Old World; and it would 
almost seem that Nature in the form of the Gulf Stream drift, 
stranded on the shores of Europe, makes a silent protest against our 
viewing this tree as a stranger in America, 

There is, however, a way out of the difficulty. It is possible that 
Cassia fistula may have been the gift of Africa to America through 
the agency either of the Main or of the North Equatorial Current 
before the discovery of the New World, but in the earlier period of 
the European colonisation of West Africa. In the first case the 
floating pods could have been transported in two or three months 
from the Gulf of Guinea to Brazil, and no doubt many of the seeds 
would still be sound. In the second case, where the agency of the 
North Equatorial Current is appealed to, the floating pods could 
have been carried in six or seven months from the vicinity of the 
Cape Verde Islands to one of the Lesser Antilles, and perhaps a few 
of their seeds would still be germinable. The intervention of the 
aborigines of the New World would be required ; but one can imagine 
that the discovery of such a singular fruit on the beach might tempt 
one of the more curious among the natives to plant its seeds. The 
tree must have been long established on the West Coast of Africa and 
on the Cape Verde Group. In those two localities in the middle of 
last century it was beginning to grow wild (Schmidt's Cap Verdische 
Flora, 1852). 

Though it is feasible that Cassia fistula may have been introduced 
into South America by the currents, assisted, as just suggested, by 
the subsequent intervention of the aborigines, it can hardly be 
doubted that the early Spaniards were the agents in establishing it 
in the West Indies. Sloane in his book on Jamaica (II., 42) quotes 
Martyr to the effect that it was planted in Hispaniola, Cuba, and 
Jamaica by the Spaniards. Sloane was writing of his experiences 
in the latter part of the seventeenth century, when, as he indicates, 
there was a trade to Europe from the New World in the fruits of 
this tree, the Brazilian fruits being regarded as superior to those 
from Egypt. In 1688-9, during his sojourn in Jamaica, the tree 
was frequently to be met with around houses and on the sites of 
plantations during the Spanish time. He takes the similar history of 
the Tamarind (Tamarindus indica), which, having been first planted 
at Acapulco by the Spaniards, was in his time widely spread over the 
West Indies. The case of the Tamarind appears to be decisive in 
this matter. 

Calophyllum calaba, Jacq. 

This West Indian and South American tree, with which I made 
my first acquaintance in the forests of Mount Diavolo in Jamaica, 
calls for only a few remarks. It contributes scantily to West Indian 
beach-drift ; but it cannot be compared, either in its station or in the 
buoyancy of its fruits, with Calophyllum inophyllum, the well-known 
current-dispersed tree of the coral atoll and of the coral-girt shores 
of the Pacific. 

Calophyllum calaba, the familiar Santa Maria tree of the West 
Indies, is a conspicuous feature of the wet forests of Jamaica and 



156 PLANTS, SEEDS, AND CURRENTS 



Cuba. It would only be found near the beach when forested hill- 
slopes descend directly to the coast. In Jamaica it is certainly not 
a littoral tree, and this is also the view of Grisebach. However, 
Descourtilz, as quoted by Hemsley (Chall. Bot., IV., 298), and 
Schimper (Ind. Mai. Strand Flora, pp. 108, 182) speak of it as a 
West Indian strand tree. 

I found a few of the small globular fruits amongst the beach-drift 
of the north and south shores of Jamaica, some of them empty and 
some of them bearing sound seeds. Fruits with sound seeds were 
picked up by Morris on the south coast of the island (Hemsley, 
Ibid.). The manner in which its buoyant fruits could reach the sea 
is indicated in the station of the tree on the banks of a branch of 
the Spanish River in the mountain forest zone of eastern Jamaica 
(Forrest Shreve in Harshberger's Phytogr. N. Amer., p. 679). I 
collected a few of the fruits amongst the foreign drift of the beaches 
of the Turks Islands, but they were either empty or contained a 
greatly shrunken dead seed. 

If this was a typical strand tree in the West Indies, with its fruits 
dispersed far and wide by the currents, we should expect it to play 
the part taken by Calophyllum inophyllum in the Pacific, as above 
referred to. We should expect to see it establishing itself on the 
sandy islets thrown up in coral-reef regions, as on the Florida sand- 
keys, and to find it included amongst the indigenous flora of a group 
like the Bermudas. Dr. Millspaugh does not mention it in the case 
of the Florida keys so systematically examined by Mr. Lansing; 
whilst it is admitted to be an introduced plant in the Bermudas, 
and apparently it belongs also to the foreign plants of the Bahamas 
(Chall. Bot., II., 21 ; IV., 298). 

Hemsley regards it as dispersed by the currents (Ibid., L, 42) ; and 
this is the opinion also of Schimper, who couples C. inophyllum and 
C. calaba together as possessing a well-developed floating apparatus 
in the shell of the fruit (p. 182). But whilst Nature has emphatically 
demonstrated that the first is dispersed by currents far and wide 
over the insular and continental coasts of the Indian and Pacific 
Oceans, she gives no consistent indications of the same kind for the 
second. In Jamaica and Cuba, C. calaba is essentially a tree of the 
inland forests, and its fruits make a very poor show in the beach- 
drift. Although it is possible that the currents might carry the sound 
fruits to a distant shore, it is scarcely likely that a tree accustomed 
to the humid conditions of an inland forest would be able to establish 
itself on a beach. However, the germinative capacity of the seeds 
appeared to be soon lost ; and in an experiment on the buoyancy of 
the dry fruits I found that whilst they all floated for two or three 
weeks, those that floated for a longer period had rotting seeds. I 
would imagine that, as compared with the Pacific species, the fruit- 
shell is more pervious to water in prolonged flotation. 

Sapindus saponaria, L. (Soap-berry) 

This is an American tree usually described as confined to Florida, 
the West Indies, and Venezuela. A specimen obtained by Forster 



FOREIGN DRIFT OF THE TURKS ISLANDS 157 



from Easter Island about 1773 was regarded by Seemann in his 
Flora Vitiensis (p. 47) as belonging to this species; and there would 
seem to be some reason for believing that the species is indigenous 
in the Marquesan and Tahitian Groups, in the floras of which it is 
included by Drake del Castillo in his work on those islands. Both 
Hawaii and Fiji have each a peculiar species; but I would refer the 
reader to my book on Plant Dispersal (pp. 325, 332) for an account 
of the difficulties connected with the distribution of the genus, and 
to Hemsley's remarks in the Botany of the Challenger Expedition 
(IV., 304) for an authoritative discussion of this point. If, as Hemsley 
observes, there are two or three Asiatic species closely allied to 
Sapindus saponaria, it may be that we are here concerned with one 
variable plant that ranges through the warm latitudes of the globe. 
In any case we are here dealing with a plant that is well worth 
studying from the standpoint of dispersal. 

Although, as stated below, the seeds of Sapindus saponaria have 
been found in the stranded drift of Jamaica, the Turks Islands, the 
Bermudas, and the Azores, it does not seem to be a littoral tree in the 
ordinary sense. Schimper (Ind. Mai. Strand Flora, p. Ill) remarks 
that it ought to be a strand plant in the New World ; but Grisebach 
gives no particulars as to its station, and I did not observe it amongst 
the shore vegetation in Jamaica. Writing of the tree in Jamaica, 
Sloane observes (IL, 132) that it grew in his time in all the " lowland 
or Savanna woods " of the island. It is, indeed, a tree of the open 
woods; and this is also the station assigned to it by Millspaugh in 
the case of the island of Cozumel, off the coast of Yucatan (Plantce 
JJtowance). From such a station its seeds would at times get into 
river-drift and be carried to the sea. In those seemingly rare 
localities, where as an intruder from the inland districts the Soap- 
berry tree grows by the beach, the dispersal of its buoyant seeds by 
currents would be facilitated. This would be the case in Florida, 
where, as Prof. Harshberger tells me, the plant grows on the sandy 
beaches of the peninsula. 

An interesting record of the occurrence of the seeds of this tree in 
beach-drift is that described by Hemsley, on the authority of J. M. 
Jones, in the case of the Bermudas (Chall. Bot., IL, 27; IV., 304). 
The plant is rare in those islands, having been first raised from seed 
washed up on the southern shores in 1841. It must thus be viewed 
only as a recent addition to the Bermudian flora ; but the important 
point is that the seed preserved its germinative powers after a period 
of flotation in the sea that must have covered several weeks, if not 
months, though man's aid was necessary to secure the establishment 
of the species. A few seeds came under my notice amongst the drift 
stranded at Paroti Point on the south coast of Jamaica. Though 
the tree is common in the island, this was the only locality in which 
I found the seeds in the beach-drift. The seeds examined had sound 
kernels and floated in sea-water. I picked up two others amongst 
the stranded drift on Greater Sand Cay, the southernmost island of 
the Turks Group; but they were afterwards mislaid, so that their 
soundness was not tested. Though occurring in scanty numbers, 
the seeds of Sapindus saponaria may, I think, be claimed as one of 



158 PLANTS, SEEDS, AND CURRENTS 



the normal constituents of West Indian beach-drift. I found no 
reference to their occurrence in European beach-drift ; but, as stated 
below, they came under my notice amongst the foreign drift of the 
Azores. 

The modes of dispersal now merit our attention. Although the 
fleshy pericarp of the fruits might attract birds, the seeds in their 
hard shells being apparently well able to withstand transport in a 
pigeon's crop without injury, there is no evidence at my disposal 
that frugivorous birds distribute the seeds. On the other hand, the 
indications of West Indian beach- drift and the stranding of the seeds 
in a germinable condition on the shores of Bermuda point unmis- 
takably to the agency of the currents. Hemsley's view that the 
seeds are dispersed by the currents (Chall. Bot., I., 43, 48; II., 27; 
IV., 304) is thus well founded, and the behaviour of the seeds under 
experiment in part confirms his opinion. 

The seeds are black, round, 10 or 11 mm. in diameter, and 
have a hard, impervious shell about 1 mm. thick. The buoyancy 
is of the type characteristic of convolvulaceous seeds, neither the 
shell nor the kernel possessing any floating power of themselves, the 
buoyancy arising from the fact that the kernel incompletely fills 
the seed-cavity. When, however, the cavity is entirely occupied, the 
seed sinks. Thus it happened that in my experiments in Jamaica 
about half of the seeds sank at once in sea-water, and about three- 
fourths of them sank in fresh-water. Of those that floated in sea- 
water about half floated after a month's immersion, and 20 or 25 
per cent, after six to seven weeks, some of the last being sound, 
whilst in others it was evident that water was beginning to penetrate 
the coverings. The weak spot in the hard shell is in the " scar," 
the umbilical aperture previously closed tending to become patent 
after prolonged immersion. Water finds its way slowly into the 
interior, the hard shell softens so that it can be readily cut with a 
knife, the kernel decays, and the seed sinks. When several seeds 
are kept in the same vessel the water has to be changed frequently, 
as the rotting kernels of the seeds that are absorbing water turn it 
putrid. 

I would imagine that few seeds would display sound kernels after 
more than two months in sea-water. This period, however, might 
be sufficient for the transport of some of the seeds in a sound con- 
dition to Bermuda from the Florida Strait; but it would be in- 
sufficient for their passage to the Azores, for which several months 
would be necessary (see Notes 12 and 14 of the Appendix). Though, 
as far as I know, the seeds have not been found on European beaches, 
their occurrence on the beaches of the Western Azores points, in 
spite of the results of my experiments, to this possibility. I picked 
up two seeds, both seemingly sound, one at Porto Pym in Fayal, and 
the other near Magdalena at the west end of Pico. But even the 
presence of these drift seeds in the Azores is inconsistent with the 
indications of the experiments. Additional investigations are needed 
before one can credit these seeds with the capacity of reaching isolated 
islands like Easter Island through the agency of the currents. 



FOREIGN DRIFT OF THE TURKS ISLANDS 159 



Drepanocarpus lunatus, Mey. 

This shrub grows in maritime swamps in the tropics of the New 
World and of the West Coast of Africa, being in both regions often 
associated with the mangroves, and especially on the African side, 
where, as we learn from Dr. Vogel's journal (Hooker's Niger Flora, 
1849), it is frequent at the coasts and in the estuaries. According 
to Grisebach it is found on the mainland of the New World from 
Mexico to Brazil, and he records it from the West Indian islands of 
Haiti, St. Lucia, and St. Vincent. In West Africa it thrives on the 
Guinea Coast and in Senegal. 

With the exception of a solitary empty pod that came under my 
notice on one of the beaches of the Turks Islands, I never found the 
fruit represented in West Indian drift, nor was it represented in the 
collection of Jamaican beach-drift made by Morris. It is therefore 
probable that neither the fruits nor the seeds are suited for effective 
dispersal by currents. Yet the opposite inference might be drawn 
from the fact that out of about fifteen known species of the genus 
only one occurs outside the New World, namely Drepanocarpus 
lunatus, and that is held in common between West Africa and 
America. De Candolle considered that this littoral species might be 
spread by the currents, but gives no data. In his Geographic Botanique 
(1855, circa p. 780) he viewed it as an American plant naturalised 
in West Africa ; and with it he links Ecastaphyllum brownei, another 
littoral plant that is both West Indian and West African, yet is 
unsuited for trans-oceanic dispersal by currents (see p. 207). This 
seems to be an unsatisfactory explanation. If valid, we should have 
to apply it to other littoral plants, e. g. Symphonia globulifera, 
which present precisely the same difficulty (see p. 243). 

Omphalea diandra, L. 

The seeds of this euphorbiaceous plant must be regarded as typical 
of West Indian beach-drift. They are black, semi-globose, one to 
one and a half inches across, and possess a hard, crustaceous shell. 
Whilst scantily represented in the Turks Islands drift, they are 
characteristic of the Trinidad beaches ; and they are included in the 
collection of drift made by Morris on the coast of Jamaica (Chall. 
Bot., IV., 302). But though about half of those collected by me on 
the West Indian beaches contained kernels, the others being often 
more or less empty, it is uncertain whether any of them would 
retain their germinative capacity after prolonged flotation in sea- water, 
the oily kernel being liable to a degenerative change that destroys 
its viability after being kept for a year or two. The kernel removed 
from its impervious hard shell floats in water, its buoyancy being 
due mainly to the lightness of the albumen, but partly also to a 
shrinkage- cavity between the cotyledons. It is thus apparent that 
the seeds, which must often be carried down by rivers to the sea, 
could be transported by the currents for considerable distances ; but 
it is very doubtful whether this would aid the oversea dispersal of a 
riverside inland plant such as Omphalea diandra undoubtedly is. 



160 PLANTS, SEEDS, AND CURRENTS 



I am not acquainted with the parent plant; but Hemsley states 
that it climbs on trees on river banks in Central and South America 
and in the West Indies (Chall. Bot., IV., 302). Pax, in the Pflanzen- 
reich monograph on the Hippomanece (IV., 147, 1912), to which the 
genus is referred, states that the distribution of this species extends 
from the Antilles and Central America to Peru and Brazil. It is 
found in the Amazon region, and here one may note Spruce's observa- 
tion of its frequency amongst the riverside vegetation of one of the 
tributaries of the Maranon branch of the Amazon on the lower 
eastern slopes of the Ecuadorian Andes (Kew Bulletin, 1909, p. 216). 

Omphalea triandra, another species, which is dealt with on p. 226, 
contributes to local beach-drift in the West Indies. Although the 
seeds float and illustrate the same type of buoyancy, they lack the 
hard crustaceous shell of those of 0. diandra, and are in this respect 
less fitted for prolonged transport by currents. 

Acrocomia 

The empty " stones " of this genus of palms are common in 
Jamaican beach- drift, and also came under my notice on the beaches 
of Trinidad, Tobago, and Grenada, being doubtless in the main 
derived from trees growing in the interior of the respective islands. 
They may be regarded as characteristic of West Indian beach-drift, 
though they are very scantily represented in the foreign drift of the 
Turks Islands. Yet it is not easy to explain at first sight their 
occurrence on beaches, since the palms especially affect savannas 
and open woodlands, and seem to have no special preference for the 
vicinity of rivers, by which the fruits could be conveyed to the coast. 
However, that they are thus carried down to the sea is very evident. 
(I have not distinguished here between the fruits of the two most 
common species of the genus, A. lasiospatha and A. sclerocarpa). 

The moist mature fruits sink in sea-water, but they acquire 
buoyancy in the drying process. However, experiment shows that 
the dry fruits will sink in a few days or in a week or so, the outer 
brittle shell being deficient at the base, which is imperfectly pro- 
tected against the penetration of water by the small perianth. The 
history of these fruits in West Indian drift is similar to that of 
Aleurites moluccana in the drift of the Pacific islands, as described in 
my book on Plant Dispersal (p. 419). The fallen fruits, having 
become light and buoyant in the drying process, are washed into the 
rivers and thus transported to the coast, where they are often 
stranded on the beaches. Whilst lying there exposed to the sun and 
rain, they are in time deprived of their outer coverings. The hard 
black " stones," about an inch across, which are thus exposed, soon 
lose their seeds through decay, and it is in this condition that they 
usually occur in the beach-drift. The seeded " stone " has no 
buoyancy either in the moist or the dry fruit. It is only when it 
is set free by the removal of its coverings on the beach, and when 
it has lost its seed by decay, that it is able to float. Each empty 
" stone " has three lateral perforations, two of which are closed at 
the bottom, but one is more or less patent. However, the sea- water 



FOREIGN DRIFT OF THE TURKS ISLANDS 161 



is unable to displace the air within, and the " stone " thus becomes 
buoyant. 

Ipomgea tuberosa, L. 

Much interest is attached to these West Indian drift seeds or 
fruits, since they remained for nearly three centuries without a 
botanical name, though often mentioned by the earlier botanists 
and other contemporary writers as figuring amongst the foreign 
drift stranded on the Orkney Islands and the Hebrides. Clusius 
(1605), C. Bauhin (1623), Sloane (1695), Petiver (1702), the two 
Wallaces in their descriptions of the Orkneys (1693-1700), and 
Pennant in the account of his tour in the Hebrides (1772), all refer 
to them, but not one of them was acquainted with their source,, 
although some, like Sloane, make correct surmises. They were 
content to describe and sometimes rudely figure them. Petiver's 
use of the name " Faba Orcadensis," though very appropriate in a 
popular sense, since the earliest recorded drift specimens came from 
that group, served rather to increase the mystery, which was not 
solved until Hemsley identified them with Ipomcea tuberosa, L., in 
his paper in the Annals of Botany for 1892 (Vol. VI.). Superstition 
played its part in the story of these strange-looking gifts from the 
sea; and, as we have seen in Chapter II., the women of the Hebrides 
are stated to have sought relief during the pains of childbirth by- 
clenching one of them in the hand. 

These fruits or seeds (their particular designation being uncertain) 
are about an inch across, depressed-globose in shape, yet slightly 
squarish in outline. The ebony-black hue, the hard, bony, polished 
shell, the four-lobed, or rather four-grooved, upper surface, and the 
large scar underneath, are characters that distinguish them from all 
other drift seeds and fruits. Grisebach states that Ipomosa tuberosa 
is distributed over the West Indian islands and occurs on the tropical 
American mainland (Mexico to Guiana), as well as in tropical Africa 
and the East Indies. Hemsley in the paper above named remarks 
that although it is usually regarded as a native of tropical Asia, 
Africa, and America, its Old World form was separated by Mr. C. B. 
Clarke under the name of kentrocaulos. " It is not " (he writes) 
" essentially a shore plant, but rather a climber of lofty trees." Nor- 
mally there are four separable seeds as in typical Ipomoeas, but 
they are closely compressed and form a spheroid. Not infrequently, 
according to Hemsley, only one seed is developed, which " assumes 
the size and nearly the shape of the four seeds combined," and 
adapts itself to the size and shape of the seed-vessel, the original 
complement of four seeds being indicated by four furrows. It may 
happen, as in the case of one of the typical drift specimens examined 
by me, that there is an appearance of two cells, each containing an 
embryo. Here we seem to be concerned with a fruit rather than 
with a seed. There is evidently much to be learned about the con- 
ditions under which this abnormal development takes place. It 
may be added that Grisebach makes no allusion to it in the descrip- 
tion he gives of the species, and that seeds gathered by me from living 
plants in Jamaica displayed no such peculiarity. 

M 



162 PLANTS, SEEDS, AND CURRENTS 



A remarkable feature is that only these abnormal seeds or fruits 
show capacity for dispersal by currents, the ordinary separate seeds 
from Jamaican plants exhibiting little or no buoyancy. The current- 
dispersed seeds, as we learn from Hemsley, are " not uncommonly 
met with in the drift of the Caribbean Sea, and are sometimes carried 
far up into the North Atlantic by the Mexican Gulf Stream." How- 
ever, only two specimens came under my notice on West Indian 
beaches, one in Jamaica and the other in the Turks Islands. They 
are represented in the Kew Museum in the Morris collection of 
Jamaican seed-drift made in 1884 ; but they were not mentioned by 
Hemsley in his account of the seeds and fruits there contained which 
is given in his report on the botanical results of the Challenger 
Expedition (IV., 284, 298, 1885). Some years passed before he 
identified them as the seeds of Ipomoea tuberosa. 

The botanical name, however, was not known to me until early in 
1913, when Dr. Rendle very kindly came to my aid and referred me 
to Mr. Hemsley's identification. Shortly afterwards I saw them 
under this name in the Kew Museum, a note on the label stating that 
they are frequently washed up on the coasts of Cuba and South 
America. The interesting feature in the story of these West Indian 
drift seeds is their occurrence on European beaches. In 1908 Mr. J. 
Fox sent one to me from the Shetland coasts, together with seeds 
of Entada scandens and Mucuna ; and there is one in the Kew 
Museum which was obtained by Colonel Fielden in the Hebrides in 
1891. Doubtless these seeds have also been gathered amongst the 
Atlantic drift on the shores of Scandinavia ; but Sernander makes no 
allusion to them in his account of the foreign seeds and fruits washed 
up on those beaches. However, it is possible that some large drift 
seeds discovered there by Lindman in 1880, which were referred to 
the Convolvulacece but had otherwise defied determination, may 
belong to this species. 

It came as a surprise to me, whilst looking up some of the early 
references to Gulf Stream drift in the British Museum library, that 
these seeds had long been known to the older botanists and to the 
early writers on the Orkney Islands. In their nameless condition 
they were almost forgotten until Hemsley wrote his paper in the 
.Annals of Botany. The historical side of the subject did not, how- 
ever, come within the scope of his paper; and this must be my 
excuse for dealing here with a matter that could have been handled 
by him in a far more authoritative and complete fashion. The list 
*of references now given is not at all exhaustive, but it will serve my 
purpose. 

Clusius, in his Exoticorum Libri (libr. II., cap. xvi., p. 41, fig. 9), 
published in 1605, described and figured without further comment 
these fruits amongst some which had been given to him by Jacobus 
Garetus. C. Bauhin, in his Pinax Theatri Botanici (p. 405), printed 
in 1623, merely cites the description of Clusius. With the aid of 
Clusius, Sloane was able to identify the fruit with one of those 
figured by the Rev. J. Wallace in his book on the Orkney Isles 
(issued in 1693) amongst other " strange beans " frequently cast 
up on those islands (Philos. Trans., Vol. XIX., p. 398, 1695-7); 



FOREIGN DRIFT OF THE TURKS ISLANDS 163 



and he also identified it with others he had often seen in collections 
of rare fruits. Though, as he says, authors were silent as to its 
source, and he himself had " never seen it grow," he rightly sur- 
mised that the sea had brought it to the Orkneys from the West 
Indies. The peculiar form of the fruit often tempted the old authors 
to make a drawing of it. Though the figures are rude, they are 
accompanied by good descriptions. 

J. Petiver, F.R.S., a contemporary of Sloane, described and 
figured the fruit in his Gazophylacium Naturce, a remarkable work 
containing 1000 illustrations of objects of natural history, and pub- 
lished with varying form and title from 1695 to 1764. Under the 
name of Faba Orcadensis, he describes it as " nigra, polita, tetra- 
sulcata, hilo magno," and, like Sloane, he refers to Clusius in this 
connection. Like Sloane, also, he alludes to its being figured in 
Wallace's account of the Orkney Isles, though in this case it is the 
son's enlarged book that is concerned. " My ingenious friend, 
Mr. James Wallace, Physician " (thus Petiver writes), " hath figured 
this in his Description of the Orckney Isles, p. 14, from whose shoars 
Mr. Will. Clerk brought it me. Father Kamel hath also sent me 
the same from the Philippine Isles." [Petiver's description of the 
fruit is given in a small octavo volume published in 1702, p. 54; 
whilst the figure it concerns is to be found in a large folio volume 
(table 34, fig. 10) issued in 1764, the contents of the first fifty tables 
being described in the smaller volume. It is ill-figured, but well 
described.] 

It is evidently to this fruit that Pennant alludes in his account of 
his Voyage to the Hebrides in 1772, which has been already quoted 
(see p. 32). After naming four kinds of " Molucca Beans " thrown 
up on this group, he says that " the fifth is a seed called by Bauhin 
'fructus exot: orbicularis sulcis nervisque quatuor,' whose place is 
unknown." He appears to have had access to Sloane's account of 
the West Indian drift seeds on the Orkney Islands ; but there is no 
reference to it. C. Bauhin's Pinax Theatri Botanici (1623, p. 405) is 
evidently the work quoted by him ; but Bauhin, as previously stated, 
had merely quoted the earlier work of Clusius. 

This discussion may be concluded with a few remarks on the 
nature and cause of the buoyancy of these 4 i composite " seeds, as 
one might term them. Of the three specimens obtained from the 
beach-drift of Jamaica, the Turks Islands, and the Shetlands, all 
floated in sea-water, but two, including the Shetland seed, sank in 
fresh-water. In other words, all were specifically lighter than sea- 
water, but two were heavier than fresh-water. This behaviour, 
interpreted in the light of a somewhat extended acquaintance with 
the subject of the flotation of fruits and seeds where the average 
specific weight happens to be near that of sea-water, indicates that 
a large proportion of these " composite " seeds produced by the 
plant would not possess buoyancy in any sense. As in the case of 
convolvulaceous seeds generally, the floating power is to be ascribed 
entirely to the cavities produced by the shrinking of the albumen 
and embryo during the hardening stage, the separate parts having 
no independent floating capacity. 



164 PLANTS, SEEDS, AND CURRENTS 



A section of one of the seeds disclosed traces of two cells, each 
holding an embryo and displaying a large shrinkage- cavity. 

Mangifera indica (Mango) 

The empty fibro-membranous " stones " of this fruit are common 
on the beaches of the Turks Islands and in West Indian beach-drift 
generally. I would imagine that those washed ashore on the Turks 
Islands were drifted there from San Domingo or were thrown over- 
board from passing vessels. Numerous small craft hailing from San 
Domingo and other islands trade in fruit in these seas. These 
materials are found all over the tropics on the beaches of countries 
where the Mango is cultivated. No doubt they often occur on other 
coasts derived from rubbish thrown over by passing ships. Prof. 
Ewart tells me that they are cast ashore on the south coasts of 
Australia; and in Chapter II. reference is made to one that was 
stranded on the coast of South Wales. 

Miscellaneous Materials in the Beach-drift of the Turks 

Islands 

Amongst these materials may be specially noticed large spines or 
prickles, pumice, floating corals, and electric-light bulbs, the second 
and third named deriving special interest from their suitability for 
carrying small seeds in their cells or crevices. 

The large Prickles of Zanthoxylum. — These large spines or prickles, 
which are rather frequent in the drift, are conical in form, and are 
apparently detached from the trunks of two species of Zanthoxylum, 
a genus including different West Indian trees. The largest prickles 
have a diameter at the base of two to two and a half inches, and 
belong perhaps to Z. clava-Herculis, the " Prickly Yellow " of the 
Jamaican. The smallest kind has a basal diameter of one and a half 
inch. These prickles would be able to withstand the transatlantic 
passage, and ought to be found amongst the West Indian drift 
stranded on European beaches. They are figured by Sloane (Vol. II., 
table 172), though not in connection with drift, under the name of 
Euonymus affinis, a tree which, he says, is very common in Jamaica. 

Pumice. — The stranded pumice usually consists of small, rounded 
pebbles, a quarter to a half inch across, which commonly occur 
amongst the smaller drift sorted out by the waves above the line of 
the heavier and larger drift. Occasionally one finds large fragments, 
as in the case of one washed ashore on the east coast of Grand Turk, 
which was seven and a half inches long and weighed one and one- 
eighth pound. It was well rounded, and was partially incrusted 
with large Serpulid tubes, 5 to 6 mm. in diameter, and with other 
marine organisms. Evidently it had been a year or more afloat, and 
might well have been transported from the other side of the Atlantic. 

Floating Corals. — Fragments of floating corals stranded on the 
beaches of Grand Turk and of the other cays, as well as on the shores 
of the neighbouring Caicos Islands, are well known to the residents, 
and are termed " floating stones." Occasionally they are picked up 



FOREIGN DRIFT OF THE TURKS ISLANDS 165 



at sea from boats sailing between the islands. They range from five 
or six inches to a couple of feet across, and all apparently belong to 
the same kind of Mseandrine massive coral with large convolutions. 
I picked up some small specimens on the beach, and examined others 
of large size which a resident had placed in his garden. The largest 
measured by me was 17 x 14 x 5 inches in size. It floated when 
placed in fresh- water, and probably weighed forty or fifty pounds. 
I was informed that larger specimens have been found. Most of the 
floating corals examined by me floated in fresh-water as well as in 
sea- water ; but in one case the coral floated only in sea- water. Many 
years ago floating corals of the same character were examined by me 
on Keeling Atoll in the Indian Ocean, and a description of them was 
given in a paper contributed to the Scottish Geographical Magazine 
for 1889. Reference may be made in this connection to Coral and 
Atolls, by Wood- Jones, 1910. 

Electric-light Bulbs. — Amongst the " odds and ends " cast up on the 
beaches of the Turks Islands are electric-light bulbs. I found three 
or four of these stout glass globes, which were all quite intact and 
would seemingly float for years. Mr. Savage English alludes, in his 
paper on Grand Cayman in the Kew Bulletin (1913), to the occur- 
rence of these bulbs amongst the " jetsam " of that island. Doubt- 
less they are discarded and thrown over from vessels. They are 
quite watertight, and suggest useful floats for current investigation, 
as they are very conspicuous on a beach. 



CHAPTER VIII 



MISCELLANEOUS PLANTS 

In this chapter numerous other West Indian littoral plants, which 
are not dealt with in the preceding chapter, are discussed from the 
standpoint of dispersal. The object has been to treat in this manner 
all the plants mentioned in the table given in Chapter IV., in which 
the relation existing among West Indian littoral plants between 
their distribution outside the New World and their capacity for 
dispersal by currents is illustrated. The small- seeded shore plants, 
which raise other considerations, are dealt with in Note 21 of the 
Appendix. 

Acacia farnesiana, Willd. 

This plant came under my notice in different parts of the tropics, 
and I made a special study of its station and modes of dispersal in 
Hawaii and Jamaica. One may begin the discussion of this widely 
spread small tree or shrub with remarking that there is some diverg- 
ence of opinion as to its distribution as an indigenous plant. De 
Candolle in his Geographie Botanique (pp. 770, 792) viewed it as of 
American origin and as naturalised in Asia and Africa. Bentham 
observed that, whilst it was difficult to determine where it was 
indigenous, it had the appearance of being so in Western America 
from Texas to Northern Chile, in tropical South Africa, and in 
Northern Australia, but not in India (Trans. Linn. Soc. XXX., 502). 
Baron von Mueller speaks of it as native of Southern Asia and the 
warm parts of Australia, and as growing spontaneously in tropical 
and subtropical America (Select Extra-Tropical Plants, 1880). The 
general opinion, however, leans towards an American origin; but 
at present we will accept three facts concerned with its distribution, 
as stated by Bentham : (a) that it is widely spread over the tropical 
and subtropical regions of the New and the Old World; (b) that it 
has been generally cultivated for the perfume of its flowers; and 
(c) that it has been frequently established as an escape from cultiva- 
tion. Further consideration of the matter may throw light on the 
plant's origin, but since we are dealing with a favourite tropical 
cultivated plant which also grows wild in nearly all warm countries 
(Hemsley, Bot. Chall. Exped., IV., 148), the initial difficulties are 
apparent. It is, however, possible that we may obtain some clue 
by regarding the outposts of its distribution, as in the case of its 
occurrence on oceanic islands. 

Let us commence with the islands of the Pacific. Wherever this 

166 



MISCELLANEOUS PLANTS 



167 



plant is found in these archipelagos, whether in Hawaii, Tahiti, the 
Marquesas, Rarotonga, Samoa, Tonga, Fiji, etc., the botanist refuses 
it a place in the indigenous flora. Its absence from the native floras 
of these islands would be readily understood, if it was not at home 
on the western borders of the Pacific, that is to say, in the regions 
comprising South-eastern Asia, Malaya, and North Australia, whence 
the Polynesian plants have been in great part derived. Yet it would 
be quite consistent if America was the home of the plant, since 
except in the very distant past there have been very few connections 
between the American and Polynesian floras. The indications 
would seem to be, as inferred by Hillebrand in the case of Hawaii, 
that the tree was introduced by the early Europeans into the Pacific 
islands. 

With the issue thus a little narrowed we will now discuss its dis- 
tribution more in detail; but numerous difficult questions at once 
present themselves. Why should this particular species of Acacia, 
we may ask, wander round the tropics of the globe, when hundreds 
of others remain restricted to their homes, principally in Australia 
and South America? Hemsley, writing about thirty years ago, 
remarked that of the three hundred Australian Acacias, this is the 
only non-endemic species (Chall. Bot., IV., 148). Found over most 
of the warm regions of the globe, it so often impresses the botanist 
with the appearance of being indigenous that, as we have seen, 
various regions have been assigned as its home. Long ago Willde- 
now placed its home in the West Indies and particularly in San 
Domingo (quoted by Schmidt in his Cap Verdische Flora). How- 
ever, it will be apparent from its behaviour in the Hawaiian Islands, 
as described later on, that the plant soon adapts itself to a new 
locality and spreads rapidly. The tendency on the part of many 
introduced plants to become thoroughly naturalised in a short space 
of time is well illustrated in this case, and the modern botanist 
with a larger experience of such cases is better able to discriminate 
in such matters. 

But a further difficulty would present itself in the variety of stations 
selected by the plant. Though they would be all consistent with 
the behaviour of a xerophilous plant, their variety would tend to 
complicate the problem concerned with the home of the species. 
It is equally at home in the arid plains of the elevated interior of 
Mexico, at the margin of the sea beaches in the West Indian Islands, 
and amongst the trees in the loamy soil bordering the mangrove belt 
in Jamaica and elsewhere. It may cover the low-lying plains of 
the sea border with an impenetrable bush as on the Gulf margins 
of Texas, or it may with other trees fringe the dry beds of streams 
in the prairies of the same region. Such is its behaviour in the 
New World as indicated by Harshberger and others, but the variety 
of its stations might be illustrated from other parts of the globe. 

Its littoral habit may be first dealt with. Though more typical 
of the belt of trees that immediately border the sandy beach, it 
accompanies certain of these trees when they grow at the edge of a 
coastal or estuarine swamp. In Java, according to Schimper (Ind. 
Mai. Strand Flora, pp. 67, 122), it is an essential constituent of the 



168 PLANTS, SEEDS, AND CURRENTS 



Nip a formation, a brackish- water swamp association predominantly 
characterised by Nipa fruticans and stretching inland in the rear 
of the coastal mangroves. But it is confined to the drier ground, 
and herds with Cerbera odollam and some other characteristic beach 
trees of the Barringtonia formation that are equally at home at the 
beach margin and at the swamp border. In Jamaica I observed it 
growing in the loamy soil behind the mangrove belt in the company 
of several other plants, such as Coccoloba uvifera, Conocarpus erectus, 
Guilandina bonducella, Hibiscus tiliaceus, and Thespesia populnea, 
that are often associated with it at the margin of the beach. When, 
as in Jamaica, it appears on the beach, it will usually be found also 
occupying the low district in the rear. But its behaviour in Jamaica 
supplies another clue. When one reflects that in the society of the 
Mesquite (Prosopis juliflora), Cactacece, Yuccas, etc., it thrives in 
the scrub of the extensive Liguanea plains in the interior (Harsh- 
foerger, p. 678), the suspicion arises that Acacia farnesiana, being 
primarily a xerophyte, only presents itself in this island as an intruder 
on the beach. 

We obtain the same clue when we glance over the other parts of 
the West Indies. Millspaugh found it growing inland on St. Thomas, 
as well as on the seashore of Porto Rico, and also at Santiago de 
Cuba (Plantce Utowance). In the case of Inagua, one of the Bahamas, 
Harshberger found it associated with Opuntia and Phyllanthus in 
the low thickets of the strand, and in the same company it came 
under my notice in the interior of Grand Turk. As in Jamaica, 
the chaparral formation, a more or less impenetrable scrub of Acacias 
(including A. farnesiana), Prosopis juliflora, Cactacece, Yuccas, etc., 
covers the arid plains of the interior of Hispaniola, an island in 
which Willdenow was inclined to look for the home of the plant we 
are now discussing. But it is not in the islands that the chaparral 
is best developed, but on the mainland, as in the arid interior of 
Mexico, Texas, and the Calif ornian Peninsula as described by Harsh- 
berger. Here amidst a motley group of xerophytes, in which 
Cactacece, Yuccas and Acacias are conspicuous, the plant we are 
now concerned with is at home; and the ever-prevailing Mesquite 
(Prosopis juliflora) is its frequent associate. When this scrub 
descends from the elevated tablelands of Mexico to the plains that 
border the Gulf and extend along the shores of Texas, Acacia farne- 
siana accompanies it to the sea-coast. In such situations its claims 
to be ranked as a strand plant would be no greater than those of 
the numerous other xerophytes of the chaparral scrub that descend 
with it to the coast. 

If the matter ended here there would be little difficulty in deciding 
the point at issue. But not uncommonly in the West Indian region 
and in other parts of the world Acacia farnesiana, as already remarked, 
discards its associates of the chaparral and takes its place amongst 
the characteristic littoral trees. Having explained how the plant 
reaches the coast from the inland regions we have now to ascertain 
why it remains there. In the answer to this question we may per- 
haps find a key to its wide distribution over the globe. It associates 
with quite different plants in the arid regions of America, Africa, 



MISCELLANEOUS PLANTS 



169 



and Australia. How comes it, we may ask, that the xerophytes 
with which it grows in those three continents are confined in the 
main to their respective regions whilst this plant occurs in all of 
them ? What advantage can this species possess over all the hundreds 
of Australian Acacias that have never wandered far from their 
home? It is not merely that it is able to adapt itself to a littoral 
station; for most xerophilous Acacias could do that; but it is able 
to maintain itself there. A shore station gives it some special 
advantage over the numerous xerophytic plants of the arid inland 
regions. They come and go on the strands of all the continents, 
but Acacia farnesiana remains. Why is that ? 

It is a matter of dispersal. The number of plants that are dis- 
persed by currents, as I have shown in the eighth chapter of my 
work on Plant Dispersal, must be very small indeed, almost infini- 
tesimal in relation to the totality of species in the plant world. 
From a somewhat extensive acquaintance with the buoyant capacities 
of seeds and fruits 1 feel on safe ground in assuming that nearly all 
the species of the chaparral scrub that reach the coast, as on the 
Gulf shores of Texas and Mexico, possess no means of effective 
dispersal by the currents. They may hold their own in places by 
force of numbers, but they cannot extend their range along the 
coast to localities where the chaparral is absent. In this respect 
Acacia farnesiana possesses a great advantage, as I found in Hawaii, 
since its indehiscent pods can float for a month unharmed in sea- 
water. Its maintenance at the coast does not depend on recruits 
from the inland scrub. It is ensured by the distribution of its 
fruits by the currents. Though the seeds themselves sink, they 
are buoyed up by the pod. 

A reference may here be made to my experiments in Hawaii, as 
the details are not given in my previous work, where only the results 
are stated. The moist green pods either sink at once in sea-water, 
or float heavily and sink in a few days. They are entirely filled 
with a kind of pith, the seeds having not yet accomplished their 
hardening and shrinking stage. When the pod is ready to fall from 
the tree, it is blackened and more or less air-dried, and the seeds 
rattle freely inside. Its prolonged buoyancy is due to the cavities 
produced by the shrinking of the seeds and the drying up of the 
pith. Of five of these dry pods placed in sea-water, one sank in 
sixteen days, the next in twenty-three days, and the others in from 
thirty-two to thirty-six days, the cause of the sinking arising from 
the decomposition of the pith and the gaping of the valves pro- 
duced by the penetration of sea- water. This is far, however, from 
the type of buoyancy one associates with fitness for trans-oceanic 
dispersal by currents ; but it is well adapted for inter-island dispersal 
in an archipelago and for extension along a continental sea border. 

The behaviour of the plant in the Hawaiian Islands is very sugges- 
tive. Regarded by Hillebrand as of early introduction it has spread 
over all the islands, and in places forms extensive coastal thickets. 
Cattle spread the seeds over an island, and they may often be seen 
germinating in their dung; but the currents accomplish the inter- 
island dispersal. On some parts of Oahu, where the shrub grows 



170 PLANTS, SEEDS, AND CURRENTS 



abundantly near the sea, the pods are washed up in great quantities 
on the beaches, and the freed seeds are to be seen germinating in 
numbers, the seedlings striking into the sand. It occurs as a char- 
acteristic beach shrub around the coasts of Hawaii, Oahu, etc., and 
has been spread by the cattle far inland. Hibiscus tiliaceus is its 
frequent associate. Spreading up some of the valleys of Oahu 
Acacia farnesiana forms extensive thickets impenetrable for cattle, 
typical chaparral scrub but of recent growth. This matter is dealt 
with at length in my work on Plant Dispersal. 

The occurrence of Acacia farnesiana in oceanic islands needs a 
little further consideration. One may suspect that this shrub or 
small tree was introduced by man into islands when they lie far 
from the continents, since its capacity for dispersal by the currents 
would probably be limited to traverses of tracts of sea not more 
than 400 or 500 miles across. Cambage ascertained that the seeds 
preserved their germinative power after an immersion of five or 
six months in sea-water (Journ. Proc. Roy. Soc. N. S. Wales, XLIX., 
1915, p. 94). But since the seeds had no buoyancy, he appealed 
to the pods. On finding, however, that a single pod sank in a few 
days, he inferred that the seeds might be carried for very long 
distances in drift-wood or pumice. This means of dispersal, how- 
ever, would be at the disposal of all the species of Acacia that happen 
to grow near the beach, and would not of itself be sufficient to explain 
the exceptional range of the species in question. He does not 
introduce the agency of man, an agency that would at once give 
the plant a great advantage over other Acacias not so favoured. 

One can scarcely doubt that this plant was introduced by Euro- 
peans at an early date into the Cape Verde Islands and Madeira, 
either from the West Coast of Africa or from Southern Europe where 
it has long been cultivated. It was collected by George Forster 
on St. Jago in 1778 (1779?), and was regarded by Schmidt in the 
middle of the last century as truly indigenous in the group {Flora 
der Cap Verdischen Inseln, 1852, pp. 38, 342). Welwitsch, who was 
in the islands about that time, refers to it as subspontaneous 
(Catalogus Herbarii Gorgonii, by Prof. Coutinho, 1914-15). It also 
seems to have been introduced into Fernando Noronha, though it 
is now behaving as an indigenous plant. The thorny Acacia bushes 
that were described by Moseley as abundant on the shore during 
the visit of the Challenger about 1874 (Chall. Bot., III., 11) were 
probably of this species. Ridley, who found Acacia farnesiana 
growing in thickets in the interior of Fernando Noronha in 1887, 
regarded it as having been introduced (Journ. Linn. Soc. Bot., vol. 
27). In 1836 an Acacia was collected by Darwin on Keeling Atoll, 
which was referred to this species (Chall. Bot., IV., 113). During my 
sojourn on the atoll in 1888 I did not observe that it formed a feature 
of the indigenous flora. It was probably one of the numerous plants 
introduced in the early days of the occupation of the islands. 

Of the several authorities on the floras of the oceanic islands of 
the tropical Pacific, not one includes this species amongst the indi- 
genous plants, that is to say, the plants found in the islands at the 
time of their discovery. Mann and Hillebrand for Hawaii, Seemann 



MISCELLANEOUS PLANTS 



171 



and Home for Fiji, Hemsley and Burkill for Tonga, Reinecke for 
Samoa, Cheeseman for Rarotonga, Jouan and Drake del Castillo 
for the Tahitian Group, the Marquesas, and the Paumotus, all in one 
way or another disclaim the plant. Many of them do not mention 
it. Seemann, however, remarks that in his time (1860) it was 
strictly confined to the gardens of white residents in Fiji. Hille- 
brand, as we have seen, regards it as a plant of early introduction 
in the Hawaiian Islands. Since he does not include it in his list of 
plants introduced by the natives in prehistoric times (p. xvi.), we 
may suppose that he places it amongst " several species of Acacia 
(that) might well claim a place " amongst plants introduced since 
the time of Captain Cook. If this was the case, Acacia farnesiana 
must have quickly become established, since in Hillebrand's time 
(1851-71) it was " spread over all the islands." Cheeseman, also, 
made a list of plants probably introduced into Rarotonga by the 
natives prior to the arrival of the white man; but this plant does 
not figure in the list. From these data, I think that it is fair to 
assume that botanists do not credit Acacia farnesiana with a pre- 
European existence in the Pacific islands. (With the exception of 
the writings of Jouan and Mann, which are quoted by Hemsley 
(Chall. Bot., IV., 148), all the works of the other authorities named 
are given at the beginning of my work on Plant Dispersal.) 

It would be possible to extend this discussion very considerably; 
but I have gone far enough to show the probability of this plant being 
indigenous in the New World. Bentham would place South Africa 
and Australia in the same category. However, Cambage included 
this plant in his recent studies of the history of the Australian 
Acacias, as indicated by their seedlings, and he looks rather to 
America for the home of the plant (Ibid., p. 97). This will remind 
us that there is another way of approaching the problem. Not the 
least valuable outcome of the studies of Andrews of the adaptation 
of plant-forms to the special conditions of Australia will be the 
sidelight often thrown on problems of this kind. The following 
considerations respecting this plant have suggested themselves after 
a perusal of his recent paper on the Leguminosce ( Journ. Proc. Roy. 
Soc. N. S. Wales, Vol. XLVIIL, 1914). From his discussion of the 
Australian Acacias I would infer that although Acacia farnesiana 
is at home in Northern Australia, it does not display the special 
Australian impress which attains its maximum expression in the 
development of the phyllode, a character of Acacias amongst which 
the plant we are discussing finds no place. The section, Gummiferce, 
to which it belongs, seems to have obtained no secure footing in 
Australia (p. 395) ; and the other types of the series, of which it forms 
one, are endemic in America, in Africa, or in Asia (p. 392). We 
could, therefore, scarcely regard Acacia farnesiana as a gift of 
Australia to the littoral flora of the tropical zone. We have pointed 
out the probability that either directly or indirectly Australia origin- 
ally supplied species of Scozvola, Dodonma, and Cassytha, that frequent 
the shores of the Old and the New World in warm latitudes ; but the 
same, it would seem, cannot be said for Acacia. 

I may conclude this discussion with the remark that Acacia 



172 PLANTS, SEEDS, AND CURRENTS 



Jarnesiana has here been taken as a sample of a small group of 
cosmopolitan tropical and subtropical plants, including such as 
Hibiscus tiliaceus and Thespesia populnea, which, though often 
differing greatly in other particulars, are linked together by the 
difficulties which their distribution presents. Equally at home at 
the coast and inland, and all capable, though to a varying degree, 
of dispersal by currents, there is always more than a suspicion that 
man has assisted for ages either directly or indirectly in their dis- 
tribution. Over all of them hangs a doubt as to their birthplace, 
since they behave as indigenous plants over most of the warm regions 
of the globe. In their present range they seem to be quite inde- 
pendent of the development centre of the genus. If the botanist 
places the plant concerned in one hemisphere, the errant species 
presents itself as to all appearance an indigenous plant in the other. 
The student of distribution quarrels with all of them in one region 
or another, since they figure too frequently as disturbing factors in 
his speculations on the history of a flora. 

Both Hibiscus tiliaceus and Thespesia populnea are treated in a 
later page, but with less detail as the writer hopes to take up the 
further study of the story of their travels around the globe. Their 
history is bound up with that of aboriginal peoples, and they raise 
somewhat different issues than does the species of Acacia with which 
we have been concerned. The names of Hibiscus tiliaceus and 
Thespesia populnea are part and parcel of the native languages 
around the tropics, and we can almost detect a linguistic affinity 
between those of the New and the Old World. On the other hand, 
Acacia farnesiana is a nameless plant, as the philologist would 
express it, around the tropics of the globe. It has names, it is true, 
but not names that belong to the language of the aborigines in whose 
country it may now grow. It has been a great traveller, but its 
story is bound up rather with the continents than with islands, 
rather with early civilisations than with states of barbarism. From 
the circumstance that it has been identified with the " Small Acacia " 
of Dioscorides, and has been even supposed by some to have been 
represented by its flowers in Egyptian tombs (Von Mueller, Ecctr. 
Trop. Plants ; De Candolle, Geogr. Bot.) 3 we may have to face quite 
other issues. 

Ambrosia crithmifolia, DC. (A. hispida, P.) 

This composite beach plant ranges all over the West Indies, 
including the Bahamas and the Florida keys and the continental 
shores of the Caribbean Sea. Growing prostrate on the sand with 
its flowering spikes rising six to twelve inches in the air, it gives a 
peculiar aspect to the surface, reminding one a little, as regards the 
foliage effects, of an English sand-dune covered with Matricarias. 
When it carpets extensive tracts of sandy plains bordering the sea, 
the aromatic fragrance of the plant is often borne far to seaward 
by the wind blowing off the shore. 

Detached from the parent plants the small dry fruits, enclosed in 
the persistent involucre, occur in numbers in the sand of beaches, 



MISCELLANEOUS PLANTS 



173 



from which they could readily be swept off by the waves and carried 
away in the currents. However, my experiments in the Turks 
Islands indicate that they possess limited floating powers. Picked 
up by the waves, and washed off the beach, they would sink in 
from two to four days. Prolonged drying for a year and more 
adds but little to their buoyancy, half of them sinking in two days, 
whilst the few remaining afloat after a week are only floated up by 
adherent air-bubbles. The achene removed from the involucre has 
initial buoyancy, but sinks within four days. Though unsuited for 
direct distribution by the currents over broad tracts of sea, these 
small fruits might be carried great distances in the crevices of a 
drifting log. They would readily be washed with the sand into the 
crevices of timber temporarily stranded on a coast. 

The achene shut up in the dry involucre would not be likely to 
tempt sea-birds, and the fruits do not attach themselves to plumage. 
The achene is 2-5 to 3 mm. in length. The length of the fruit with 
the persistent involucre is 4 mm. 

The genus holds fifteen known species, of which all but one are 
confined to the New World. The exception is a widely spread 
Mediterranean shore plant (Ambrosia maritima, L.) which extends 
to the coast of Senegal. Certain of the species range far and wide as 
waste plants and weeds in the American continent and in the West 
Indies. Some North American species frequent estuarine marshes, 
whilst others prefer the sand-prairies of the interior and the borders 
of salt swamps in inland regions (Harshberger). 

I found Ambrosia crithmifolia thriving on six of the ten cays of the 
Turks Islands, and reference to it in this connection will be found in 
the chapter on the flora of these islands. Mr. Lansing's observations 
on the Florida sand-keys, where he found it growing on five of the 
nineteen keys examined, indicate that it is one of the earlier plants 
to occupy land newly gained by accretion from the waves. Yet the 
fact that it has not been observed in Bermuda, which has received so 
many West Indian strand plants, militates against the efficacy of the 
currents in transporting it across broad tracts of ocean. 

Anacardium occidentale, L. (Cashew-nut) 

The nuts of this West Indian tree, which is only indigenous in the 
New World, do not form a feature in the beach-drift of these regions. 
On one occasion I found a solitary decaying nut on a Jamaican 
beach; but that alone could not entitle it to be regarded as a drift 
fruit. Yet it is interesting to note that Gunnerus, who lived in the 
middle of the eighteenth century, found this fruit on the Norwegian 
coast; but Sernander in his book on the Dispersal-Biology of the 
Scandinavian flora (p. 117) tells us that it has not been found since. 
Hemsley, who quotes Linnaeus on this point, says that the seed was 
in a living condition, and he places the fruit among those certainly 
or probably distributed by currents (Chall. Bot., I., 43 ; IV., 278, 305). 

This Norwegian drift fruit has puzzled me much, since Linnaeus 
gives no other particulars concerning it. The large fleshy peduncle 
could not possibly be here concerned, unless it was thrown over 



174 PLANTS, SEEDS, AND CURRENTS 



from some vessel near the Norwegian coast ; whilst it is scarcely- 
likely that the heavy nut when fresh could have much buoyancy. 
This is indicated in one of my experiments. I placed in sea- water 
some sound nuts which had been gathered rather over a year. After 
a few days the pericarp began to soften, and in ten days all the nuts 
were at the bottom of the vessel, a week being the average flotation 
period. Empty nuts are much lighter and might float longer. 

Anona palustbjs, L. 

The genus Anona, or, as it is now usually written, Annona, has 
been fortunate in its latest monographer, Dr. W. E. Safford, who 
has recently published in volume 18 of the Contributions from the 
United States National Herbarium for 1914 a classification of the 
genus. Here we are mainly concerned with the littoral and estuarine 
tree above named ; but from the distribution standpoint it cannot be 
treated without some reference to a few of the general features of 
the genus to which it belongs. 

" The genus Annona " (writes Dr. Safford, p. 4) " is confined 
almost exclusively to tropical and subtropical America. At an early 
date, however, certain species were introduced into the warmer 
regions of the Old World for the sake of their edible fruits, and 
were described as distinct. In addition to these there are a few 
species endemic in tropical Africa." The author gives no numerical 
account of the distribution of the genus in his paper. Failing this, 
a general statement of the results for about 120 species named in 
the Index Kewensis may be given. Here about 100 species are 
exclusively American. Of the balance most are tropical African, 
and the rest occur in Madagascar, the Mascarene Islands, Ceylon, 
China, and Malaya, with one species, A. palustris, both American and 
African, the only species common to the Old and the New Worlds. 
Some emendation is, however, here required respecting the few 
Asiatic species named in the Index Kewensis, since Dr. Safford 
informs me that " there is no endemic Anona in Asia. . . ." The 
manner in which the edible species, the Sops, the Custard Apples, 
the Cherimoya, etc., have been spread over the world by man, not 
only in recent times but by the early European navigators, suggest 
that human agency may have been effective in this direction, even 
in prehistoric times. (Dr. Safford tells me, in a letter since received, 
that " certain economic species were introduced into India at a 
very early date.") 

It is a significant fact that the only species which links together 
the Old and the New Worlds, the cultivated species being excluded, 
is one of the plants of the mangrove association, namely, Anona 
palustris, a tree that finds its home in estuaries and in coastal swamps. 
As far as I can ascertain there is no other species that could be 
regarded as a littoral plant. There are one or two species like 
A. paludosa, Aubl., that grow in marshy situations at the coast, 
but they also occur inland. Nor are there any plants that are 
exclusively confined to the vegetation bordering the sandy beaches. 
Where such plants grow in sandy plains at the coast they belong 



MISCELLANEOUS PLANTS 



175 



to an association of inland xerophilous plants that in places descend 
to the sea-border. We would therefore expect that Anona would 
illustrate the principle exemplified by many tropical genera, such as 
Barringtonia, Calophyllum, Clerodendron, Cordia, Guettarda, Morinda, 
Sccevola, Terminalia, etc., that where a genus comprises both coast 
and inland species only the coast species possess seeds or seed-vessels 
adapted for effective dispersal by currents. This principle, which 
is laid down in the second chapter of my book on Plant Dispersal, 
might be considerably extended now, and the indications especially 
concerning Anona will be stated below. But a few remarks on the 
station characteristics of the genus are first required, as well as some 
preliminary observations on its means of dispersal. 

The capacity of the genus for adapting itself to very different 
stations is remarkable. Some species are at home in the humid 
conditions of the dense mountain forests; others thrive in the drier 
conditions of the open- wooded districts ; others grow in the savannas 
and grassy plains; others are found in the sandy plains near the 
coast, and others in the desert rocky regions in the company of 
xerophytic Cactacece, Agaves, and Acacias. A few live in inland 
and coastal marshy districts, and one is the associate of the man- 
groves at the borders of estuaries and in the swamps at the sea- coast. 
Probably the xerophytic habit is most typical of the Anonas of our 
own day; but as indicative of a tendency to resume, what I would 
regard as the primeval habit and station of the genus, these plants 
even in their driest stations tend to gather along the streams, and 
where the conditions are too arid for permanent streams they may 
be found in the dry rocky beds of the channels that serve as water- 
courses only during the rains. I would consider that the genus was 
primarily a denizen of wet forests in warm latitudes, and that it has 
often become adapted to drier climates during the differentiation 
of climate in later ages. 

The modes of dispersal of these plants may be now discussed. 
The question is at once raised when we contrast the distribution of 
Anona palustris, the only species common to the eastern and western 
hemispheres, with other species that are restricted to one or other 
of the two hemispheres. Dr. Safford in a letter to Prof. Harshberger, 
which is given below, strikes a true note regarding this tree when 
he writes : " If it were birds that distributed the seeds, why would 
not the more attractive species be just as widely dispersed? The 
seeds may possibly be borne by currents." The answer to this 
query' is indicated below, and it would seem, as far as these data 
can guide us, that although birds and other creatures may be effec- 
tive agents in local dispersal, the currents come into play when 
broad tracts of ocean have to be crossed. That Anona seeds are 
swallowed by fruit-eating birds of the pigeon family is stated by 
Gosse in his Birds of Jamaica (pp. 308, 315 ; 1847). Both the Pea 
Dove (Zenaida amabilis) and the White-belly Pigeon (Peristera 
jamaicensis) feed upon them. Parrots no doubt feed on the fruits, 
though I don't know whether they would swallow the seeds. One 
of the Mexican species is named " the little custard apple of the 
parrots " (Safford, p. 55). Pigs, iguanas and alligators are also 



176 PLANTS, SEEDS, AND CURRENTS 



stated to be partial to these fruits, one species (Anona palustris) 
being known in Jamaica as the Alligator Apple. 

Since none of the Anona seeds examined by me are impervious to 
water, it is unlikely that they would be able to withstand the injurious 
effect of the digestive fluids of birds for more than a few hours. It 
is quite possible that a pigeon might transport them unharmed 
across a strait two hundred miles in width, but that would be the 
limit. We must look for other agencies, therefore, to explain the 
case or cases where broad tracts of ocean have presumably been 
traversed by the species ; and when the fruit of such a plant is inedible 
and the species is not likely to have been spread by man we must 
appeal to the currents. If in addition to these features we find that 
the plant concerned is a denizen of coast swamps and is associated 
with mangroves that are well known to be distributed by currents, 
then the presumption in favour of the current hypothesis becomes 
very strong, and we would expect to find that the seeds of all other 
species, where the question of oversea transport is scarcely raised, 
would be ill-fitted for crossing an ocean in a current. It is not a 
matter of fruit-buoyancy, since the floating fruit would soon break 
down, as is illustrated in the case of that of Anona palustris in a 
later page, and the fate of the species would be ultimately determined 
by the behaviour of the liberated seeds. 

What, therefore, we may ask, is the behaviour of seeds of Anona, 
when their buoyancy is tested? The answer to this question is 
indicated on p. 177 ; and though the seeds of only five species have 
been experimented upon, the data go to show that Anona comes 
into line with many other tropical genera where only the littoral 
species are adapted for dispersal by currents. 

It will be learned from the results tabulated on p. 177 that it is only 
the littoral species with inedible fruits and seeds capable of floating 
a long time in sea- water that occurs outside the New World, namely, 
on the coast of tropical West Africa. This species, Anona palustris 
(syn. A. glabra), deserves a special discussion. 

We may best begin with Dr. Safford's letter to Prof. Harshberger, 
which is given on p. 155 of the latter' s paper on the vegetation of 
South Florida (Trans. Wagner Free Institute of Science, Philadelphia, 
October 1914) : 44 A letter of query directed to Dr. W. E. Safford, 
who has monographed the genus Annona, as to the means of dis- 
tribution of the custard-apple, elicited the following information under 
date of August 20, 1912 "— 

" Dear Sir, 

44 1 have the honour to acknowledge the receipt of your 
recent letter in which you ask suggestions as to how the swamp- 
apple, Annona glabra, is dispersed. This is a question which has 
perplexed me. The associations of this plant are with species of 
so-called mangroves of wide distribution. This species itself occurs 
on both sides of tropical America, the Galapagos Islands, and the 
West Coast of Africa. It would be interesting to find out whether 
detached branches take root readily in the mud. The wood is so 
light, it is called corkwood, and the roots are used for corks and 



MISCELLANEOUS PLANTS 



177 



Remarks 


The spongy tissue 
is the only part 
of the fresh seed 
that possesses 
independent 
buoyancy 


Ditto 


Ditto 


Ditto 


Ditto 


Amount of Spongy 
Buoyant Tissue lining 
the Seed-shell 


Scanty. Mostly 
at the hilar end 


Soanty 


More scanty than 
with Anona 
muricata 


Scanty 


Well developed 


Buoyancy of Seeds 


Moist, fresh seeds 
sink. Seeds dried 

for six months 
float from two to 
four days 


Seeds dried for six 
months sink in a 
day or two 


Seeds dried for six 
months sink in a 
day or two 


Seeds dried for six 
months sink in 
a day 


Fresh seeds float 
for weeks and 
months 


uit Edible 
■ Inedible 
for Man 1 


Edible 


Edible 


Edible 


Edible 


inedible 


psi 


o 












n, etc. 


Coast 










Wild. Not 
cultivated. 

Muddy 
shores of 
estuaries and 
borders of 
mangrove 
swamps 


Statio 


Inland 


Wild in 
woods. Also 
cultivated 


Wild. Also 
cultivated 


Wild in for- 
ests, thickets, 

and dry 
plains. Also 
cultivated 


Wild. Also 
cultivated 




Distribution 


Tropical 
America 


Tropical 
America 


Tropical 
America 


Tropical 
America 


Pacific and 
Atlantic 

coasts of 
tropical 

America and 

coasts of 
tropical 

West Africa 


Species 


Anona muricata, 
L. (Sour Sop) 


Anona reticulata, 
L. (Custard Apple) 


Anona squamosa, 
L. (Sweet Sop) 


Anona cherimolia, 
Lam. (Cherimoya) 


Anona palustris, L. 

syn. A. glabra, L. 

(Alligator Apple, 
Swamp ,, 
Monkey „ 
Pond 

Custard ,, 
of South Florida) 



<D 00 



N 



178 PLANTS, SEEDS, AND CURRENTS 



floats for nets. An experiment might be made by breaking off 
limbs or roots, and after soaking them for a time in salt water plant 
them in mud. I cannot find that their fruits are any more buoyant 
than other Annonas. If it were birds that distributed the seeds, 
why would not the more attractive species be just as widely dis- 
persed? The seeds may possibly be borne by currents. They say 
that the fruit is eaten by aquatic lizards, or iguanas of the Bahamas. 
I wonder if they are carried from island to island. ..." (It may 
be noted here that according to Fawcett and Rendle in their work 
on the Jamaican flora the light wood is used for corks, floats, etc., 
nothing being said of the roots. — H. B. G.) 

The ground covered by this extremely suggestive letter will be 
traversed in the following discussion respecting Anona palustris. 

The distribution of this plant in the New World extends on the 
Atlantic side from South Florida and the Bahamas over the Greater 
and Lesser Antilles to the South American mainland. On the 
Pacific side it is at home on the coasts of Central America, the Gala- 
pagos Islands, and on the coast of Ecuador, its southerly extension 
beyond the Peruvian borders being prevented by the aridity of the 
climatic conditions, which bring the mangroves and their associated 
plants to a halt in this region. On the West Coast of Africa it grows 
on the coasts and estuaries of Senegambia and in the Niger region. 

Its station is at the borders of the mangroves, and it is at home 
on the muddy banks of estuaries. I found it to be one of the most 
frequent trees on the banks of the Guayas estuary in Ecuador, where 
they were overflowed at high water. Here it was associated with 
Rhizophora mangle, Hibiscus tiliaceus, and other trees. It is a 
constituent of the mangrove formation on the coasts of the Virgin 
Islands in the West Indies and of the island of New Providence in the 
Bahamas (Harshberger's Phytogr. Surv. N. Amer., pp. 687, 690-1). 
It does not appear to be frequent now in Jamaica. I did not come 
upon it myself in the Black River district, though in the recent 
volume on the Flora of Jamaica by Fawcett and Rendle, where only 
two localities are given, this is one of them. A fruit was brought 
to me from the north side of the island. 

But one of the most interesting localities where Anona palustris 
occurs is in South Florida, where, as we are told by Prof. Harshberger, 
from whose memoir on the region the following details are taken, 
this tree offers one of the most remarkable formations. In these 
low-lying levels it occurs thirty to forty miles from the sea in an 
area which has been for ages undergoing a transition from its con- 
dition of submergence beneath the Gulf Stream in later Tertiary 
times to one of marsh and swamp, and finally of dry land. The 
greatest development in this region is a forest of "an almost pure 
growth " of this tree, which, varied by an occasional cypress (Taxo- 
dium distichum), forms a band usually two to three miles in breadth 
for a distance of about thirty miles along the south and south-east 
shores of Lake Okeechobee, passing on its southern side into the 
marsh formation of the Everglades. Two or three of the islands 
in this lake support a dense growth of this tree. In some places 



MISCELLANEOUS PLANTS 



179 



the Anon a trees, when within a distance of five or six miles from the 
coast, blend with an outer zone of cypress swamp. In other places 
where they approach the coast they are associated with Rhizophora 
mangle, in others, again, they largely form hammocks, or groups 
of trees., that rise up like islands in the midst of the marsh vegeta- 
tion of the Everglades. One of the characteristic developments of 
the tree occurs in the Banana Holes., which are shallow depressions 
or sinks, in which water often collects., where flourish a variety of 
other plants. Chrysobalanus icaco, Cladium, Phragmites, Sabal. Sagit- 
taria, Salix. Typha, etc. 

From what has been said it would thus appear that in South 
Florida this tree has many associates of a very different kind, and 
we may regard its behaviour there as the story of a tree of the man- 
grove formation that has been endeavouring for ages to gain for itself 
an inland station. 

As regards the modes of dispersal of Anona palustris it is likely, 
as suggested by Prof. Harshberger (p. 116).. that the seeds are locally 
distributed by frugivorous birds. He also adopts the suggestion of 
Dr. Safford that it is distributed by its light, corky wood, fragments 
of the tree being carried by water. Observation and experiment 
will show whether this last mode of dispersal is effectual. However, 
a very effective method of dispersal came under my notice in the 
Guayas estuary in Ecuador, a method described ten years ago in 
my book on Plant Dispersal (pp. 488-9). Very frequent in the 
floating drift of the river off Guayaquil were the seeds of this tree, 
often in a germinating condition. The seeds were liberated by the 
decay of the floating fruit, which was also common in the river-drift. 
They occurred commonly amongst the materials afloat in the Gulf 
of Guayaquil, ten to twenty miles off the mouth of the estuary, 
and were washed up on the beaches thirty miles to the south. Ex- 
periments showed that the seeds will float in sea-water until they 
rot and decay — one experiment covering eleven weeks, none of the 
seeds sinking, though several had become putrid. Seeds from 
Ecuadorian and Jamaican trees behaved in the same way. 

The tendency of the seeds to germinate whilst afloat in rivers 
raises an objection against their fitness for dispersal by currents, 
since sea-water would probably kill the germinating seed. Here a 
good deal depends on whether the small embryo has begun its growth 
within the albumen before the seed reaches the sea. In the resting 
condition the embryo is only about one-sixth of the length of the 
nucleus of the albumen, which is about 11 mm. long, and the cotyledons 
are minute. Considerable growth of the cotyledons takes place 
within the seed at the expense of the albumen before the tip of the 
radicle protrudes : and ultimately the cotyledons occupy almost 
the length and breadth of the seed nucleus. It is therefore apparent 
that a great deal depends on whether the embryo has passed beyond 
the resting-stage before the seed reaches the open sea. When the 
embryo is about one-third of the length of the nucleus, the tip of 
the radicle, which abuts against the pervious hilar end of the seed, 
has for its sole protection a thin membranous layer of albumen. 
In the resting seed, the embryo is better protected by the albumen 



180 PLANTS, SEEDS, AND CURRENTS 



for an oversea traverse; yet even here the impervious outer skin 
is deficient at the hilar or radicular end of the seed. 

A curious feature in the buoyant behaviour of the seeds of Anona 
palustris is that they are, like other seeds of the genus, permeable to 
water and air. When dry they behave hygroscopically and vary in 
weight 2 or 3 per cent, according to the humidity of the surrounding 
air. Fresh and moist from the fruit they owe their floating powers 
entirely to the layer of cellular tissue lining the seed-shell, no other 
part of the fresh seed possessing independent buoyancy. An exami- 
nation of seeds that had been afloat some weeks showed that until 
they became water-logged or saturated with water, there was no 
soaking of water into the seed substance, but rather a vital process 
of absorption of water, such as occurs in seeds imbedded in the 
ripe fruit. Seeds that had been afloat for three weeks, after being 
placed in a dry state in the water, were found to have taken up water 
only to the extent that it occurs in seeds in the fruit, the interior 
of the seed being fairly dry. Sufficient moisture had been absorbed 
to restore the normal moist condition of the seed as it lies in the 
fruit, and the embryo had resumed its original full outlines. There 
were no signs of saturation. 

A point of importance is concerned with the degree of salinity 
that the floating seeds of Anona palustris will withstand without 
injury to their powers of germination. In the river Guayas the 
germinating seeds were floating unharmed in brackish water that 
at high water had a density of about 1-003. From the association 
of this tree with the mangroves, the germinating fruits and seeds of 
which are not affected by sea-water, it is probable that its seeds 
can germinate in brackish water, though it is not likely that they 
would do so in pure sea-water. Nor do I think that the Anona 
trees would thrive in pure sea-water. The muddy banks of the Guayas 
estuary, on which they flourish, are overflowed by brackish water 
at high tide. But more observations on this point are needed. 
These trees grow in brackish water in the Bahamas (Harshberger, 
p. 691); and it is apparent that on the South Florida coasts, where 
they are associated in the swamps with the mangroves, the water 
must at least be brackish. But they are only halophilous by force 
of circumstances. Their great development in the inland regions 
of South Florida has taken place around fresh-water lakes, and 
such conditions are evidently the most congenial for their growth. 

A singular point arises as to the practical bearing of these observa- 
tions and experiments on the occurrence of Anona palustris on both 
sides of the tropical Atlantic. It is just possible that the seeds 
could safely traverse the Atlantic in the Main Equatorial Current 
from the Gulf of Guinea to Brazil, a passage which would require 
a period of two or three months, this being the only available trans- 
atlantic route for seeds of their floating capacity. Yet Anona is 
now almost exclusively an American genus, and if there has been 
an interchange America has the first claim to be considered the 
giver. But this would compel us to suppose either that the seeds 
had been able to withstand the six to eight months' passage involved 
in the Counter Equatorial Current, or that they could accomplish 



MISCELLANEOUS PLANTS 



181 



unharmed the long trans-oceanic passage of about two years from 
the West Indian region in the Gulf Stream drift to the West Coast of 
Africa. We are here presented, therefore, with a dilemma such as 
was offered by Chrysobalanus icaco, one that could be evaded only 
by postulating a common centre of dispersion in high northern 
latitudes in a warmer geological age. This postulate seems the 
more probable, since, as Dr. Safford informs me, Anona senegalensis, 
a typical shrub or tree, that extends from the East to the West Coast 
of Africa, is " apparently most closely related to certain species 
growing on the plains of Southern Brazil and Paraguay " (letter 
cited). 

A word may here be said on the synonymy of this species. Dr. 
Safford conclusively shows (p. 14) that the two plants to which 
Linnaeus originally applied the specific names of glabra and palustris 
belong to one species. But it is possible that under the same specific 
type may be also included Anona klainii, Pierre, of the West Coast 
of Africa, which is at all events " very closely allied to A. palustris, 
if not identical with it." Dr. Safford, whose work has here been 
quoted (pp. 5, 15) tells me that the seeds of the two cannot be dis- 
tinguished. I would point out that whilst on p. 15 this author 
speaks of these two species as on the West Coast of Africa, he alludes 
to them on p. 5 as on the eastern coast of the continent. That the 
West Coast is the true habitat is, however, indicated in his letter to 
me. Prof. Urban, as he shows, formed the same opinion of the 
close affinity of the two forms. 

In conclusion, reference may be made to a curious abnormality 
frequent in the seeds of another species of Anona (A. muricata). 
Here the cotyledons are separated by a thin sheet or film of the 
endosperm, about half a millimetre in thickness, which occupies 
the length and breadth of the seed-kernel with the exception of a 
deep notch in its base for the hypocotyl. It is best examined after 
the embryo has begun to grow, and is about half the length of the 
seed. 

Astro caryum 

Empty fruits of different species of this genus of palms were 
identified at Kew amongst my beach-drift collections from the Pacific 
and Atlantic sides of the Panama Isthmus. They were also included 
among the Morris collection of Jamaican beach-drift (Chall. Bot., 
IV., 304). I found them occasionally on the Trinidad coasts ; but 
they did not come under my notice on the beaches of the Turks 
Islands. However, since I came upon a typical specimen on the 
coast of Pico in the Azores, it would seem likely that they would 
reach the shores of Europe. The drift fruits are always empty. 
They are rather like miniature coco-nuts, and are usually about 
1J inch or 31 mm. in length. 

AVICENNIA NITIDA, Jacq. 

This mangrove is found all over the West Indies and along the 
continental coasts and estuaries of the warm regions of the New 



182 PLANTS, SEEDS, AND CURRENTS 



World, as well as on those of the West Coast of Africa. There will 
be no necessity to discuss here the station of this tree in the outer 
zone of the mangrove swamp, and I will limit my remarks here 
to the part played by the young seedlings, on being freed from the 
fruit coverings, in distributing the plant. 

In my book on Plant Dispersal (p. 489) mention is made of the 
abundance of these seedlings in the lower course of the Guayaquil 
River in Ecuador, and of their being carried out to sea and stranded 
in numbers on the coasts near the estuary. Germination com- 
mences on the tree, and it is in this condition that the fruit 
usually falls into the water of an estuary. There it floats, and 
the seedling soon frees itself from its envelopes and floats away. 
The germinating fruits were to be observed in numbers thrown up 
on the beaches of Jamaica, Trinidad, Tobago, etc. It is important 
to note in this connection that sea- water is not injurious either to 
the germinating fruit or to the freed seedling, and that the seedling 
could be transported for considerable distances unharmed in the 
sea. It has been shown by Dr. Millspaugh that with the two ether 
mangroves, Rhizophora mangle and Laguncularia racemosa, Avicennia 
nitida is one of the earliest plants to establish itself on the Florida 
sand-keys. All three mangroves have made their home in the 
Bermudas. 

The germinating fruit and the freed seedling might retain their 
vitality a considerable time after being stranded on a beach. In 
Jamaica I took five fruits on the point of falling from the tree. 
They were on the eve of rupturing, and I inferred from the con- 
dition of other fruits in the same stage that each of them contained 
a dark-green, well-developed seedling. They were allowed to dry 
in a room, with occasional exposure in the sun, for twenty-five days, 
during which period three of them opened. They were then placed 
in fresh- water, and within a week two of them were growing healthily, 
notwithstanding that they had lost just 50 per cent, of their weight 
in the drying process. 

Avicennia seedlings offer the only means of the dispersal of the 
plant by currents, and although considerable tracts of ocean might 
be safely crossed in this manner, it is not at all probable that they 
could accomplish unharmed the long transatlantic passage in Gulf 
Stream drift from the New to the Old World. On the other hand, 
they seem sufficiently hardy to survive the much shorter passage 
of from two and a half to three months in the Main Equatorial Current 
from the west coast of Africa to Brazil. Avicennia is regarded as 
an Asiatic genus, and according to this view the borrowing of its 
species from the Old W T orld by way of the West Coast of Africa would 
be quite consistent. As regards the time occupied in the traverse 
in the Main Equatorial Current, it would be similar to that taken 
up in the passage from the Florida region to the Bermudas, namely,, 
two to three months, a passage that Avicennia seedlings must have 
once safely performed previous to the establishment of this mangrove 
on those islands. (See Note 14 of the Appendix respecting Bermuda 
bottle-drift.) 



MISCELLANEOUS PLANTS 



183 



BORRICHIA ARBORESCENS, DC. 

This is a maritime Composite shrub, usually two to three feet high y 
which is very typical of the warm regions of the New World. It 
belongs to a genus exclusively American and comprising only two 
allied species, of which the present one ranges over the West Indies 
and tropical continental America, whilst the second (B. frutescens r 
DC.) grows in the Southern United States and in Mexico, both species, 
being indigenous seaside plants in Bermuda (Chall. Bot., II., 45)*. 
Although we are only concerned here with the wide-ranging species^, 
it is highly probable that the results of my observations on the 
dispersal capacities will apply to both. 

This shrub commonly frequents rocky stations at the coast, but 
it also grows on sandy beaches and on the dunes in their rear. It 
often presents in the same locality two forms, one with glabrous, 
foliage and the other with leaves covered by a silvery down; but 
both kinds of leaves may occur on the same individual. The writer 
specially studied the plant from the dispersal standpoint in Jamaica 
and in the Turks Islands. Its most critical habitat is in the Florida 
sand-keys, where we see in operation the earliest stage of plant- 
stocking in these regions, so well observed by Mr. Lansing and 
described by Dr. Millspaugh (Field Columbian Museum, publ. 118, 
Bot. Ser., 1907). After the mangroves it takes a place amongst the 
first seven or eight strand plants that occupy the newly formed 
islets in these seas. 

The next critical habitat is Bermuda, since the question of the 
fitness of the fruits for transport by currents across broad tracts; 
of sea is at once raised. The achenes, including the short crown,, 
are from 4 to 5 mm. long ; but there are no hairs nor any means off 
attaching the fruits to plumage. Looking to the currents for a* 
possible explanation of the wide range of the plant, I tested the 
buoyancy of the fruits both in Jamaica and in the Turks Islands. 
In my Jamaica experiments they sank after soaking in sea-water 
for a day or two. In those made in the Turks Islands on the plants- 
of that group, the fruits floated on the average six or seven days r 
the limit being ten days; but in a later experiment in England on- 
fruits of the same set, which had been kept for fifteen months, they- 
floated on the average nine or ten days, the limit being seventeen 
days. In such experiments it is requisite to select the achenes. 
very carefully, since from insects and other causes it is often not 
easy to find achenes with sound seeds. 

In the light of these results it is evident that the original fruits 
could not have reached Bermuda by their own floating powers, 
a passage, as shown in Note 14 of the Appendix, that would usually 
occupy nearly three months. Nor can we appeal to the agency of 
sea-birds, since the dry fruits would not be likely to be swallowed by 
them, whilst, as already remarked, they do not adhere to plumage*. 
We are thus driven to conjectures. It may be suggested that the 
achenes were accidentally introduced into the Bermudas with the 
salt brought from the Turks Islands in the seventeenth century.. 
In those times there was a regular trade between the two groups in 



184 PLANTS, SEEDS, AND CURRENTS 



this article, as shown by the report of Mr. F. H. Watkins on the salt 
industry of the Turks Islands (Colonial Reports, Miscell., No. 56, 1908). 
As the plant thrives around the creeks and ponds that supply the 
salt-pans on Grand Turk, it is not improbable that the original 
achenes might have been contained in salt shipped to Bermuda. 
But against this view there is the fact that the plant was cultivated 
before 1699 in England at Hampton Court from Bermudian sources 
(Chall. Bot., II., 45). On the whole it would seem most likely that 
the original fruits were transported to the Bermudas buoyed up 
in the miscellaneous Gulf Stream drift that is stranded there in 
quantities. 

Cakile 

My remarks on this genus will be mainly directed to the question 
of dispersal. The history of the investigation of the genus is sym- 
bolical of the history of its specific differentiation as a single wide- 
ranging variable type. At first, when the known forms were few, 
the genus was often regarded as monotypic, or as holding only one 
species with fixed geographical varieties in the Old and New Worlds 
and typified in Cakile maritima, the well-known European form. 
In the next stage each side of the North Atlantic was credited with 
a solitary species. As the inquiry proceeded, more particularly 
after Asa Gray had separated the two common American plants 
from the European C. maritima, the balance of distribution was 
transferred to the American side of the Atlantic. In that direction 
the later investigations have in the main advanced ; and whatever 
view we take of the limits of the species it cannot be gainsaid that 
the genus is preponderantly American. 

There is, however, a disconcerting lack of agreement amongst 
later investigators as to the limits of the species. Most of the diffi- 
culties seem to be due to the different results obtained from the use 
of the leaf and fruit characters in the distinction of forms. Having 
encountered such difficulties, Dr. Millspaugh made a discriminative 
study of the fruits and seeds of the specimens in the principal herbaria 
of the United States and defined the relations of the American 
plants with those across the Atlantic, the results being published 
under the title of Plantce Utowana? (Part I. a) by the Field Columbian 
"Museum (Chicago, 1900). He distinguished ten species, eight being 
American and two European, no species occurring as an indigenous 
plant on both sides of the Atlantic. In the Index Kewensis, including 
the supplements up to 1910, ten species are enumerated, of which 
seven are exclusively American; but only six of the species given 
by Millspaugh are named. The more recent investigators, including 
:Schulz in Urban's Symbolce Antillance (1903), seem to have laboured 
^towards the reduction of the species, and I note that Fawcett and 
Rendle in their Jamaican Flora (1914) speak only of four species 
in the genus. 

However, these differences of opinion concerning the limits of 
the species do not affect the distribution of the genus, which may be 
regarded as restricted, with the exception of a representation in 
the region of the Great Lakes of North America, to the western 



MISCELLANEOUS PLANTS 



185 



and eastern sea-borders of the North Atlantic in tropical and tem- 
perate latitudes and including the West Indian and Caribbean 
region ; but the genus on the eastern side of the ocean does not seem 
to extend south of Madeira and North Morocco. A curious feature 
of the distribution is that the genus is not represented by indigenous 
species on the Pacific shores of the American continent. Harshberger 
gives no locality on those coasts ; and Millspaugh regards the only 
species which he locates on the Pacific side (C. edentula at Berkeley, 
California) as introduced. 

The uncertainty about the limits of the species does not make my 
task an easy one. I have made the acquaintance in their homes 
with three of the species in four different regions, namely, in the 
south of England, in the Azores, in the West Indies, and on the Pacific 
Coast of North America. The West Indian species, with which I 
was familiar in Jamaica and in the Turks Islands is Cakile cequalis 
(L'Her.), which has been united by Schulz with two other species 
(named after Cuba and San Domingo) in C. lanceolata. The fusion 
somewhat extends the range of C. cequalis, which already had the 
reputation of being the most characteristic and widest spread of 
the Antillean species. Thus extended, the range covers the Greater 
and Lesser Antilles, including the Bahamas and the Florida keys, 
and reaches to the Bermudas. It comprises also the continental 
coasts of the Mexican Gulf and the Caribbean Sea, past Yucatan to 
Colombia. It is the species of the Turks Islands; but, except in 
one island, it is there uncommon. I only noticed it on Greater 
Sand Cay, where it was represented by a single clump, and on Grand 
Turk, where it grows in abundance. Since it was found on Grand 
Turk by Hjalmarsson in 1858, more than half a century before my 
visit, it would seem that it has long since attained the limit of its 
colonising powers in the Turks Islands, its scanty distribution over 
the group being probably due to the havoc executed by the breakers 
of those tempestuous seas on the shores of most of the islands. In 
Jamaica I observed it on the north coast and west end of the island, 
at White River, St. Anne's Bay, Dry Harbour, and Negril; but 
localities on the south coast are given by Fawcett and Rendle. 

The species of the Azores is confined to one locality, Porto Pym 
on Fayal. It is regarded by Millspaugh as introduced and as belong- 
ing to Cakile edentula (Bigel.) ; but Trelease views it as referable 
to C. americana (Nutt.). From Lowe's description of a common 
species in Madeira under the name of C. maritima, it would seem to 
be similar to the Azorean plant. Further particulars concerning this 
matter will be found in Chapters XVII. and XIX. under the Azores. 
The species observed by me in 1896 on the Golden Gate beach at 
San Francisco was probably the same species that, as we learn from 
Millspaugh, has been introduced into San Francisco Bay (C. edentula). 
There seems to be no indigenous species on the Pacific coasts of the 
New World ; and this disposes of the statement in my work on Plant 
Dispersal (pp. 431, 432) that the genus is represented by indigenous 
species on both sides of North America. My observations on Cakile 
maritima, the common European species, are given in the work just 
named. The few notes since made on the coasts of South Devon 



186 PLANTS, SEEDS, AND CURRENTS 



and Cornwall are concerned with its transient occupation of the 
beaches in places usually within reach of the wash of the waves at 
the higher tides. A few individuals occupy a beach for a season 
or two, then disappear, and two or three or more years elapse before 
the species again gets a footing. 

An interesting feature in the distribution of the American plants 
is the occurrence of two Atlantic coast species (C. americana and 
C. edentula) on the shores of the Great Lakes. Here in the society 
of other beach plants of the same Atlantic beaches, such as Lathyrus 
maritimus, Euphorbia polygonifolia, Psamma arenaria, etc., these 
maritime species have found a home on the borders of inland fresh- 
water lakes. This invasion of what is now the interior of a continent 
is regarded by Harshberger (p. 222) as having taken place during 
the post-glacial submergence of these regions. Such a change of 
station throws some suspicion on the determining influence of the 
halophilous inclination when it is so readily thrown off. In this 
connection one is inclined to recall Kearney's discovery that the 
amount of salt in sea-beaches is a negligible quantity, and to ask 
oneself what constant character in the organisation of Cakile plants 
we can associate with the double station on a sea-beach and on the 
shores of a fresh- water lake. (For comment on Kearney's discovery 
see Harshberger in Proc. Amer. Philos. Soc, 1909.) 

That the currents are active dispersers of these plants may be 
inferred from their frequent occurrence in isolated islands, as exem- 
plified below in the case of Cakile lanceolata, though from facts to 
be subsequently given it may be doubted whether the most buoyant 
fruits could safely cross a tract of sea more than 300 or 400 miles 
in width. The difficulties likely to be encountered before a footing 
can be obtained on an island in the open sea have already been 
mentioned in the case of the Turks Islands. But they are also 
illustrated in the case of the Florida sand-keys which are for the 
most part curving sand-banks, raised three or four feet above the 
sea. Although Mr. Lansing noted the occurrence of Cakile fusi- 
formis on twelve of the nineteen keys examined by him, the species 
was as a rule merely represented by a few scattered clumps, and 
in only two or three instances was it fairly frequent. Always it 
formed the outposts of the sand- vegetation on the weather side of 
the key. But Cakile may experience the same difficulties on Euro- 
pean beaches in obtaining a footing beyond the reach of the waves 
in stormy weather. What the waves give, they can also remove, 
was the lesson taught to me by Cakile on English beaches. 

On a long beach on the north coast of Cornwall it would be typically 
represented by solitary clumps of C. maritima lying far apart and 
all below the highest line of drift. They are derived from stranded 
fruits that have germinated in the drift, of which results may be 
seen in the numerous seedlings growing in the midst of the rubbish 
heaped up by the waves. It is in the upcast wrack of the Norwegian 
beaches that this species of Cakile flowers and fruits (Sernander, 
p. 123). 

Cakile lanceolata is the West Indian species most characteristic 
of small isolated island-groups. Thus it occurs in the Cayman 



MISCELLANEOUS PLANTS 



187 



Islands, on the Alacran Shoals, and in the Bermudas. That the 
Bermudas received their representatives of the genus through the 
currents is the opinion both of Hemsley and Millspaugh. Though 
its capacity for dispersal by this agency is variable, as is shown in 
the table below, it is significant that the species which has made its 
home in Bermuda is the plant that may exhibit the greatest buoyancy 
in its fruits. Yet in this there is a difficulty, since the drifting 
passage from the West Indies to Bermuda would occupy ten or 
twelve weeks (see Note 14 of the Appendix); whereas my experi- 
ments indicate that under the most favourable conditions the fruits 
of C. lanceolata would on the average float for only three or four weeks. 

A similar point is raised by the occurrence of Cakile maritima, the 
European species, in Iceland. It is shown in my experiments that 
its fruits are not suited for crossing a tract of sea much over 100 
miles in width, whilst the Faroe Islands, the nearest land to the 
eastward in the direction from which they must have come, are 
almost 250 miles away, and a drifting passage against the prevailing 
winds and currents is involved. It would be easier for fruits of 
West Indian species of Cakile to reach Iceland in the Gulf Stream 
drift so often cast up on its shores than for those of C. maritima to 
traverse the distance that separates it from Europe, provided that 
the fruits possessed in both cases the floating power. But the passage 
from the West Indies would occupy many months, and the unfavour- 
able climatic conditions would in themselves inhibit the establish- 
ment of a West Indian plant. A clue may be offered when we 
regard the associates of C. maritima on the Icelandic beaches, namely, 
Armeria maritima, Glaux maritima, Lathyrus maritimus, Matricaria 
maritima, Mertensia maritima and Silene maritima (see Babington 
in Journ. Linn. Soc, XL, 1871). From the data for five out of these 
six associates given in my book on Plant Dispersal, it is to be inferred 
that only two of the plants, Lathyrus maritimus and Matricaria 
maritima, would have reached Iceland by the currents. In the case 
of Mertensia maritima, about which I possess no data, dispersal by 
currents would seem most unlikely. Three or four of the associates, 
which occur on both sides of the Atlantic and extend into Arctic 
latitudes, raise quite other questions than those of dispersal. On 
the whole I am inclined to hold that the Icelandic strand flora, in 
which the genus Cakile takes a part, mainly reflects the effects of 
past changes in circumpolar distribution and is but little concerned 
with the currents. 

Taking the case of Cakile lanceolata as representing both potentially 
and actually the limits of possibilities for the dispersal of the genus 
by currents, we may, I think, accept the conclusion, which is war- 
ranted by the facts given below, that currents may effectually dis- 
tribute the plants along continental coasts and between islands 
100 to 200 miles apart. Currents will not explain the existence of 
the genus on both sides of the North Atlantic. We must look for 
the explanation in a common centre of dispersion of the genus in 
Arctic latitudes when warmer climatic conditions there prevailed. 
In other words, we must appeal to the theory advocated by Dyer 
which is discussed in Chapter XV. 



188 PLANTS, SEEDS, AND CURRENTS 



Coming to the mode of dispersal of this genus by the currents 
it may be at once observed that it is the upper article or joint of the 
fruit that is alone concerned. It is deciduous and readily detached 
from the dry fruit, whilst the lower joint remains firmly fixed to the 
stalk on the plant. The buoyancy arises from the development 
of spongy air-bearing tissue in the upper article, which is very light 
when dry and buoys up the enclosed seed which itself sinks in sea- 
water. As shown in the subjoined table, the floating capacity will 
usually allow the seeds to be carried between 150 and 200 miles. 
Flotation in sea- water, as indicated by my experiments on the fruits 
of C. lanceolata and C. maritima does not affect the germinative 
capacity of the seed, nor in fact does prolonged immersion after the 
fruits have sunk affect it. Martins found that germination took 
place after fruits of C. maritima had been in sea- water for forty-five 
days, though it is more than doubtful, as is brought out in Note 4 
of the Appendix, whether they floated for more than a fraction of 
this period. In my experiments germination occurred with fruits 
of C. lanceolata that after floating for a week had lain for several 
days at the bottom of the vessel. The lesson of the experiment 
of Martins is that a submersion of forty-five days in sea- water will 
not destroy the germinative capacity of the seeds of Cakile. 

The restricted floating capacity arises from a weak point in the 
buoyancy equipment. The suture between the lateral halves of 
the joint is exposed in the face of the articulation at its base; and 
it is here that the water ultimately penetrates into the interior and 
deprives the article of its floating power. In old weathered fruits 
this suture becomes more or less patent in the face of the articulation 
and there is a slit-like opening. From this cause the buoyancy of 
the joints is not always constant, as is shown in the different behaviour 
of those of Cakile lanceolata obtained from Jamaica and the Turks 
Islands. 

Nevertheless, although the buoyancy as a rule is limited, there is 
abundant evidence in the beach-drift of different regions that the 
currents are effective agents in dispersing the fruits over limited 
tracts of sea. I found the joints of Cakile to be characteristic con- 
stituents of the smaller beach-drift in the south-west of England 
(Cornwall and Devon), in Jamaica, and in the Turks Islands. Ser- 
nander also alludes to them as occurring plentifully amongst the 
Scandinavian beach-drift (pp. 122, 156, etc.). In all these localities 
several of the stranded fruits were observed to be in a germinating 
condition, and not infrequently seedlings were to be noticed growing 
among the stranded drift- materials. 

One may here direct attention to the very interesting suggestion 
made by Dr. Millspaugh that the differentiation of the species of 
Cakile is a response to the requirements of dispersal by currents. 
"The evolution for floatage" (he writes) "seems to have reached 
its height in the new species growing upon the Alacran Shoals " 
(C. alacranensis of Millspaugh). Here there is a great development 
of spongy tissue in the upper joint ; and it is argued that " the 
species-generating force in the genus seems to have been the develop- 
ment of the fruit for disseminating the plants." Prolonged investiga- 



MISCELLANEOUS PLANTS 



189 



tion and an abundance of fresh materials would be needed before 
one could discuss this important point. 

In the table subjoined are incorporated the results of the author's 
flotation experiments on the upper joints of different species of 
Cakile from several regions. It may be inferred from the data 
there given that the floating powers may vary considerably even in 
the same species. In two of the columns the results are applied to 
the transport by currents. A drifting rate of fourteen miles a day, or 
one hundred miles a week, is taken as representing the usual distance 
that would be covered under favourable conditions. 

Cakile Flotation Experiments 



Results of experiments by the author on the floating capacity in sea-water of the 
upper joints of the fruits of different species of Cakile. (See explanation above 
given.) 



Species of Cakile 


Locality of 
Collection 


Flotation Period 
in Days 


Capacity for 
Transport by Cur- 
rents stated in 
miles at the rate 

of 14 miles a 
day, or 100 miles 
a week 


Age of the Fruits 
when collected 


Aver- 
age 


Maxi- 
mum 


Aver- 
age 


Maxi- 
mum 


C. maritima . 


Cornwall 


7 


10 


100 


140 


Recent 




Cornwall 


7 


9 


100 


130 


Seven months 




Devonshire 


7 


10 


100 


140 


Recent 


C. lanceolata 


Jamaica 


25 


35 


350 


500 


Recent 




Turks Islands 


3 


5 


40 


70 


Recent 




Turks Islands 


5 


7 


70 


100 


Fifteen months 


C. edentula . 


Azores 


9 


12 


130 


170 


Recent 



The number of fruits experimented on ranged from six to fifteen. The term " re- 
cent " is applied to fruits that were experimented on at periods varying from a few 
weeks to two or three months after they had been gathered in the dry state from the 
plant. 

Additional Experiments. 

The buoyancy in sea -water was also tested in the case of some fruits (upper joints) 
of the following species very kindly sent to the author by Dr. Millspaugh. As they 
had been collected several years before, and since only three fruits could be used in 
each experiment, it seemed best to separate the results from those given above. The 
maximum results obtained for the flotation period were as follows — 

Cakile americana from Lake Michigan 5 days. 
C. edentula from Lake Michigan 12 days. 
C. alacranensis from the Alacran Shoals 20 days. 
C. fusiformis from Dog Key, Mississippi 21 days. 

Canavalia obtusifolia, DC. 

This creeping or climbing plant has established itself on the beaches 
of the warm regions of the globe, for instance, on the Pacific and Atlan- 
tic coasts of tropical America, on both the east and west shores of 



190 PLANTS, SEEDS, AND CURRENTS 



tropical Africa, in the islands of the Indian Ocean, in the Malayan 
Islands, and in Polynesia. With the exception of the African 
coasts, which I have not visited, it came under my notice in all 
the above regions. It ranks with Ipomoea pes-caprce as one of the 
most ubiquitous of tropical strand plants. 

Yet, in spite of its world-wide distribution in tropical regions and 
of the fact established by observation and experiment that the seeds 
are dispersed by currents, the seeds present a strange fickleness 
of behaviour under the test of experiment. The plant has been 
discussed in detail in my book on Plant Dispersal; but I will here 
allude to the results of buoyancy experiments given in that work 
(p. 579). Of freshly gathered seeds placed in sea- water in Fiji 
only 10 per cent, as a rule floated after three months. Of seeds 
which had been kept for three years 50 per cent, floated after eleven 
weeks. In an experiment on recently collected seeds in Jamaica 
40 per cent, floated after a month. The explanation of this behaviour 
is that on the average only 70 per cent, of the seeds are impervious 
to water, a result obtained from more recent experiments and re- 
corded in the author's Studies in Seeds and Fruits (p. 94). But the 
proportion of impermeable seeds varies considerably, being sometimes 
more and sometimes less ; and at any rate the impervious seeds can 
float for long periods. The impermeable seeds retain their germinative 
capacity for a long time. Prof. Ewart found that seeds, sixteen 
years old, were able to germinate, though sulphuric acid was required 
to start the process (Ibid., p. 96). 

The seeds were commonly observed by me in the drift of the 
Eijian beaches and also on the coast of Ecuador, as well as on both 
sides of the Isthmus of Panama, the plants being usually noticed 
in the vicinity. I found them afloat in the drift of the Rewa estuary 
in Fiji, and they were collected by Moseley amongst a number of 
other floating fruits and seeds off the coast of New Guinea (Chall. 
Bot., IV., 291). Though neither the seeds nor the plants were observed 
by Treub on the shores of Krakatau three years after the great 
eruption of 1883, the plant was found established by Penzig in 1897 
and by Ernst and others afterwards. I came upon the seeds in 
the beach-drift of different parts of the Jamaican coast, and they 
were obtained by Morris from the beaches on the south side of the 
island (Chall., Bot. IV., 291). They also came under my notice on 
the beaches of St. Croix, Tobago, and other islands. 

The plant is universally distributed in the West Indies, and there 
were few beaches visited by me that did not display it. It occurs 
all round Jamaica, and I found it on nearly every beach examined 
on the north, south, and west sides of the island. It was rarely 
observed growing away from the coast. However, in Tobago I 
noticed it a mile inland and about 250 feet above the sea. In the 
Turks group it is very rare, and was only remarked on two of the 
ten islands — namely, on Salt Cay on the east side, where a fair-sized 
colony was thriving on the beach, and on Grand Turk, where it was 
represented only by a solitary seedling growing in the beach-drift 
and evidently derived from a seed thrown up by the waves. Accord- 
ing to Millspaugh it was recorded by Lansing from seven of the nine- 



MISCELLANEOUS PLANTS 



191 



teen sand-keys lying west of Key West off the Florida coast ; but in 
all but two cases it was only represented by a single colony. The 
plant grows commonly on the Bermudian beaches. 

It would be unnecessary to give all the data relating to the wide 
distribution of this shore plant in the warm regions of the New 
World; but a reference to a few localities which have particular 
interest may here be made. In the first place, its occurrence on the 
Pacific coast is not usually stated. However, I found it on the 
Ecuador coast at Puerto Bolivar and on the beach at Panama. 
Then, again, Harshberger includes it among the strand plants of 
the delta of the Mississippi and of the Louisiana coast (Phyt. Surv. 
N. A., pp. 215, 444). In some localities it grows in great profusion. 
Thus Millspaugh at Santurce, Porto Rico, found it growing on sandy 
fields near the sea " in great quantity, massing the surface of many 
acres " (Plantce Utowance). Amongst interesting insular localities 
may be mentioned Fernando Noronha. Though it was not recorded 
by Hemsley amongst the collections made by Moseley during the 
voyage of the Challenger (1873-76), Ridley observed it growing 
plentifully in 1887 ( Journ Linn. Soc., vol. 27). 

It may be remarked in connection with the statement now and 
then made that the floating pods assist in the dispersal of the species, 
that this would not happen under normal conditions. The pod 
dehisces on the plant and often discharges its seeds with some force, 
a habit common with legumes, where the valves develop a spiral 
twist when drying. A detached fruit which I had placed in the sun in 
Tobago burst with an explosion like that of a pistol and threw the 
seeds ten to twelve feet away. Should an unopened pod be torn 
from the parent plant and carried off by the waves, the attachment 
of the valves would soon be loosened and the seeds would soon be 
liberated and float away. 

Cassytha filiformis, Linn. 
Cassytha Americana, Nees 

Since Bentham unites the wide-ranging American form Cassytha 
americana with the widely distributed Old World form C. filiformis, 
we have here a species spread over the warm regions of the globe, 
in Asia, Africa, America, and Australia, but chiefly, as Hemsley 
remarks, in maritime districts (Chall. Bot., IV., 185). It is one of the 
Dodder Laurels, a tropical genus holding at least fifteen or sixteen 
species, of which two-thirds are Australian. It is noteworthy that 
this species has been recorded from almost every group of the tropical 
Pacific, from the Paumotu Archipelago and Tahiti to Fiji and north- 
ward to Hawaii. When I met with it in the West Indies I renewed 
acquaintance with a plant with which I had already been very familiar 
in Hawaii and Fiji, the results of my numerous observations in the 
Pacific being given in my previous book on plant dispersal in those 
regions. 

In Hawaii this parasite is occasionally found growing on the beach 
plants, but it prefers the lower open-wooded region and especially 
the surface of old lava-flows near the coast. In Fiji it is typ. ^ally 



192 PLANTS, SEEDS, AND CURRENTS 



a shore plant, but it habitually extends far inland in the savannah- 
like plains on the dry sides of the islands. It is, however, as a littoral 
plant that it seems to be most frequently mentioned in the Old 
World. In the Malay Peninsula, as we learn from Ridley, it is com- 
mon in open sandy country near the sea (Trans. Linn. Soc. Bot., 
III., 267; 1888-94). On the numerous coral islands of the Java Sea 
it grows very luxuriantly, covering the woody and herbaceous 
plants with a felt-like coat (Schimper's Plant Geogr., p. 341, and 
Ind. Mai. Strand Flora, p. 188). It is stated below that after the 
eruption Cassytha filiformis established itself among the strand 
plants of Krakatau. As Prof. Scott Elliot tells me by letter, it 
crawls over the low bushes and covers the surface of coastal sand- 
dunes in Madagascar. In the West Indies this plant occupies 
similar stations. Whilst it is characteristic of the savannahs and 
lower woods of Jamaica, it is also found at the coast. Millspaugh 
observed it trailing over the beach sand-dunes on Cayman Brae 
and in similar situations on Porto Rico (Plant. Utow.). In the 
Bahamas it grows over the shore plants and is found in the thicket 
formation inland (Harshberger's Phyt. Surv. N. Amer., pp. 691, 
693-4). In South Florida it is a plant of the coastal dunes and 
of the east-coast pinelands (Harshberger, Trans. Wagner Inst. 1914, 
pp. 70, 92, 93). Over the West Indian Islands this parasite is 
widely distributed, and it ranges in the New World from South 
Florida and Mexico to Brazil. 

In the Pacific Islands I found that its small fruits, whether from 
coast or inland plants, were able to float unharmed in sea-water 
for months. On the other hand, fruits obtained by me from the 
moist lower woods of Jamaica displayed no buoyancy, even after 
being kept for years, the unfilled space in the fruit-cavity to which 
the floating power is due being absent in this case. The floating 
capacity is probably as a rule developed in stations where xerophytes 
thrive, as on the coast and in savannahs. 

From its frequent station at the coast, and from its occurrence 
in small coral islands, it cannot be doubted that the currents take 
advantage of the buoyancy of the fruits to disperse the plant. As 
long ago pointed out by Schimper frugivorous birds would also aid 
in the distribution, the fruits in the moist condition being likely 
to attract birds. In fact, fruits have been found in the crops of 
pigeons shot in the Pacific Islands (Hemsley, Chall. Bot., L, 46). 
Whether birds or currents first carried the fruits to Krakatau after 
the eruption of 1883 is not known. It appears, however, that 
the plant was first recognised there in 1897, and that in 1906 it was 
well established amongst the strand vegetation (Ernst's New Flora 
of Krakatau). 

It seems highly probable that this plant is a gift from the Old 
to the New World through the agency of the currents. In this 
respect the behaviour of the genus is closely similar to that of Scaevola 
as described under the shore plants of that genus. Like Sccevola 
the genus is predominantly Australian, eleven out of the sixteen 
known species being peculiar to that region. Of the remainder, 
three are peculiar to Africa, one is common to Ceylon and Borneo, 



MISCELLANEOUS PLANTS 



193 



and lastly there is the cosmopolitan species we have been discussing. 
Fawcett and Rendle, from whose work on the flora of Jamaica these 
facts of distribution are taken, follow Bentham in regarding Cassytha 
filiformis and C. americana as one species. The parallel between 
Cassytha and Sccevola becomes still closer when we reflect that the 
only species recorded from the New World is in each case the only 
species that is common to the western and eastern hemispheres, 
namely, C. filiformis and Sc. plumieri. A somewhat similar parallel 
is offered by Dodoncea, another Australian genus, which is dealt 
with under the head of D. viscosa. 

In their suitability for being dispersed by frugivorous birds there 
is another point of resemblance between the genera Cassytha and 
Sccevola. In neither genus, however, could we often appeal to this 
agency for trans-oceanic dispersal. In this respect I have somewhat 
changed the point of view adopted in my previous work (p. 71). 

Chrysobalanus icaco, L. (Coco Plum) 

This shrub has a special interest, because it is not only widely 
distributed in the tropics of the New World but also grows in West 
Africa. It has an edible fruit, and its occurrence on the opposite 
sides of the Atlantic raises much the same questions that are raised 
by the Hog Plum, Spondias lutea, which has the same distribution. 
Both have the reputation of possessing edible fruits, which, however, are 
not very palatable in the raw state except to animals. With both 
there is a suspicion that the aborigines may have aided their dispersal, 
and in both the agency of the currents has been invoked. The 
efficacy of the last agency is more assured in the case of the Hog 
Plum, which is discussed at length in Chapter VI. ; but for the Coco 
Plum the ground is not so certain, as is explained below. However, 
it should be remarked that two eminent botanists, De Candolle and 
Hemsley, basing their inference on general considerations, regard 
the plant as dispersed by the currents, though the first named 
looks upon the interference of man as equally probable (Geographie 
Botanique, pp. 784, 792; Chall. Bot, L, 43; IV., 279). 

From the data given by various authorities it is apparent that 
Chrysobalanus icaco ranges in the New World from South Florida 
and the Bahamas through the West Indian region to Trinidad, and 
from Mexico through Central America by way of Venezuela to Brazil. 
It evidently grows on all the larger West Indian islands and on most 
of the Lesser Antilles. In the New World the species may be viewed 
as possessing two forms, an inland form restricted to that hemisphere 
and a coast form found also in tropical West Africa. The inland plant, 
originally differentiated as C. pellocarpus, Mey., frequents moist 
woods; whilst the coast plant is a typical shrub of the vegetation 
lining the beach. (I have here followed Fawcett and Rendle in 
their union of the two species in their Jamaican flora. This was the 
view of De Candolle, and the exigencies of distribution long since 
compelled me to support his opinion.) 

We must therefore expect to find very different stations assigned 
to this shrub. This is illustrated in Jamaica, where, according to 



194 PLANTS, SEEDS, AND CURRENTS 



Fawcett and Rendle, it may be found on the seashore and inland 
at elevations up to 3000 feet. Disregarding its inland stations, I 
will here refer to my observations on its occurrence at the coast 
on this island and to those of others in the West Indies and in West 
Africa. It is instructive to notice its associates, and they are suf- 
ficiently varied to cause reflection. At Falmouth (Jamaica) it grew 
on the drier ground of the coast flats behind the Batis-Salicornia- 
Sesuvium association of the muddy borders of the mangrove belt, 
and in the company of Guilandina bonducella, Coccoloba uvifera, 
and Borrichia arborescens. On the south side of the island, to the 
east of the Black River and opposite the Salt Lakes, it grew on a 
strip of sea-beach fronting the inland marshes in the society of a 
Pancratium, and served as the host of a conspicuous yellow-coloured 
Loranth (Phoradendrori). In the Virgin Islands it is found amongst 
the trees bordering the beach, such as Coccoloba uvifera, Hippomane 
mancinella, and Thespesia populnea ; and in the Bahamas it grows 
on Watling Island behind the Tournefortia-Suriana association in 
the company of Genipa clusiifolia and Coccoloba uvifera (Harshberger, 
Phyt. Surv. N. Amer., pp. 686, 690). On the beaches of South 
Florida and on the dunes in their rear Coccoloba uvifera, the Seaside 
Grape, is still the constant associate of the Coco Plum, Chrysobalanus 
icaco, an association on which light may be thrown when we deal 
with the plant first named (Harshberger, vide infra). 

But it is apparent that Chrysobalanus icaco is also a characteristic 
plant of the great fresh- water morass of the Everglades in the heart 
of South Florida. There it thrives in the patches of forest, known 
as the " hammocks," that rise up in the midst of the swamps and 
serve as sanctuaries for the West Indian vegetation that ages since, 
when the region of the Everglades was submerged beneath the 
Gulf Stream, occupied low islands rising up in a shallow sea. It is 
at home also in this swampy interior at the edge of the cypress 
swamps and at the borders of streams. In the company of such 
typical West Indian littoral and estuarine plants as Hippomane 
mancinella (Manchineel) and Anona palustris, Chrysobalanus icaco 
has been for ages a denizen of the Everglades (Harshberger in Trans. 
Wagner Inst., Philadelphia, 1914, pp. 67, 70, 135, 172 ; and Phyt. 
Surv. N. Amer., 1911, pp. 230, 698). 

In the tropics of the African West Coast, where the Coco Plum 
is stated to be very common, it figures as a characteristic littoral 
plant. Writing of the coast near the mouth of the River Nun, Dr. 
Vogel observed in his journal that " the strand is clothed with 
jungle close to the sea, consisting of Chrysobalanus icaco and Ecasta- 
phyllum brownei," the last named being also a West Indian littoral 
shrub (W. J. Hooker's Niger Flora, 1849, pp. 35, 336). 

In the dispersal of this species both birds and currents have played 
a part. Although its fruit would attract pigeons and birds of similar 
habit, we could only appeal to such an agency in the case of inter- 
lsland dispersal. The protection of the relatively thin-walled stone 
would of itself be insufficient to enable the seed to withstand with- 
out injury a sojourn of several hours in a bird's crop, and this 
unfitness would be emphasised by the imperfectly filled hole at 



MISCELLANEOUS PLANTS 



195 



one end of the stone, which in time would admit the gastric 
fluids. 

My observations on the suitability of the fruits for transport by 
currents were made in Jamaica on coast plants. The drupaceous 
fruits are about an inch long, have a crustaceous fleshy covering, 
and enclose a prominently ribbed stone (nearly as large as the entire 
fruit), the walls of which are about 2 mm. thick. Inside is a single 
seed which does not quite fill the cavity, and it is to this empty 
space that the buoyancy of the dry fruit is due. But the seeds 
often fail in a large number of fruits. In one locality I found that 
only 10 per cent, were seeded. In the case of more or less empty 
fruits there will usually be found the remains of two seeds, and 
investigation showed that each of the two ovules, forming the ovular 
complement of the genus, had developed into seeds, which, after 
attaining a size of 3 or 4 mm., aborted and shrivelled up. Such empty 
fruits, though useless for purposes of dispersal, are readily transported 
by the currents 

The fruits in the form of the dry more or less bared stones rarely 
occur in the Jamaican beach- drift, and when found are usually 
empty. It was in this condition that I found most of the fruits 
in the beach-drift of the Black River coast and of the coast near the 
White River on the north side of the island. The fresh fruit floats 
at first ; but I should not imagine that it would float for a long time, 
unless the failure of both seeds had resulted in an empty seed-cavity. 
The dried stones as they lie under the plants are much more buoyant. 
Four of these selected stones, which had been gathered a few months, 
were placed in sea-water After two months they were all afloat, 
and of two cut open one proved to have a sound seed and the other 
a rotting seed. I should greatly doubt, however, whether the 
currents, where a period of flotation exceeding two or three months 
is involved, would prove to be effective agents for the dispersal 
across an ocean of any sound fruits. A canal, which at one end of 
the stone leads into the seed-cavity, is merely filled with soft tissue 
that would in time permit the penetration of sea- water, thus bringing 
about the death of the seed. 

As regards dispersal by currents, the absence of this plant from 
such a well-examined group of islands as the Bermudas is significant, 
since so many West Indian strand plants have been carried there 
through this agency. Nor can we appeal to the presence in the 
Bermudas of its constant West Indian associate, Coccoloba uvifera, 
since its indigenous character is doubtful, a matter referred to when 
dealing with that plant. It is highly improbable that fruits with a 
sound seed could ever cross the North Atlantic with the Gulf Stream 
drift, though one might expect to find occasionally on the shores 
of Europe an empty stone or one with the seed decayed. Nor could 
the fruits withstand the six or eight months' immersion involved in 
a passage to West Africa in the Counter Equatorial Current, even 
if such a traverse was feasible. The chances that the currents could 
carry the stone with a sound seed from the New World to tropical 
West Africa may be thus ruled out. On the other hand, a capacity 
of floating in the sea for two or three months without injury to the 



196 PLANTS, SEEDS, AND CURRENTS 



seed would just bring these fruits within the scope of the agency 
of the Main Equatorial Current as a carrier of drift from West Africa 
to Brazil. Though the greater number would probably not survive 
this test, the few that did so would find on the first sandy coast 
congenial conditions for establishing the plant. Its spread over the 
West Indian region through the influence of the same swift current 
would naturally follow. But before considering the possibility 
that the New World has derived this species from West Africa, a 
few remarks may be made on the distribution of the genus. 

There can be no doubt that the genus is preponderantly American, 
whatever view we may take of the limitations of the species. Of the nine 
species given in the Index Kewensis, five are peculiar to the New World, 
three to the Old World (mainly Africa), and one is common to both 
worlds. By some the species are regarded as fewer, but the American 
preponderance remains. There is thus a basis of support for De Can- 
dolle's original contention (Geogr. Bot., pp. 784, 792) that the species 
common to both worlds, Chrysobalanus icaco, is American in origin. 
On the other hand, this plant was regarded by J. D. Hooker and 
Bentham as " possibly introduced " into America from Africa 
(W. J. Hooker's Niger Flora, p. 336). We are thus on the horns 
of a dilemma. If De Candolle is right, and certainly the ancient 
story of the plant in the Florida Everglades gives support to his 
view, it could not have been a gift from America to the Old World 
under the present arrangement of the Atlantic currents. If Hooker 
and Bentham are right, we can appeal to the currents, but we have 
to face the facts that the genus is predominantly American and that 
the plant in dispute has been for ages a denizen of the Everglades. 
Then we have the singular feature, which Chrysobalanus holds in 
common with several tropical genera existing in both worlds, a 
feature indicated in the fact that the only species linking the western 
and eastern hemispheres together are littoral plants that could 
only cross the Atlantic by the agency of the currents in its narrowest 
portion between Africa and Brazil, the implication being that Africa 
would here figure as the giver and not as the recipient. The easiest 
way out of this disconcerting situation may be to adopt the view that 
we are not primarily concerned with means of dispersal, and that 
the original centre of dispersion of the genus lay in the north. In 
other words, the hypothesis advocated by Dyer may remove most 
of our difficulties. 



CHAPTER IX 



miscellaneous plants (continued) 

Coccoloba uvifera, L. (Seaside Grape) 

This is one of the most familiar of the trees growing by the sea- 
shore in the West Indies. It is able to adapt itself to a variety 
of stations at the coast. Thus, it often grows among the trees and 
shrubs lining the sandy beach, when it is associated with Chrysoba- 
lanus icaco, Ecastaphyllum brownei, Guilandina bonducella, Suriana 
maritima, Thespesia populnea, etc. But it is almost as much at home 
on a low, rocky coast in the company of the Seven-year Apple (Genipa 
clusiifolia), and may not infrequently be found in the mangrove- 
border association, growing either with Conocarpus erecius on the 
flanks of the Laguncularia fringe or with Avicennia on the mud-flats 
bordering salt-water lagoons. Where low, sandy plains lie behind 
the beaches, it may extend some distance inland. 

It belongs to a genus peculiar to the tropics of the New World 
and holding a large number of species, 140 and more, that find their 
principal station in the mountain forests and on the open-wooded 
plains of the West Indies, Central America, and tropical South 
America. This shore tree, which varies greatly in size, is spread 
over the West Indian region, ranging from South Florida and the 
Bahamas to Trinidad, and extends along the eastern borders of the 
continent from Central America to Venezuela, the Guianas, and Brazil. 
It grows in the Bermudas, and, although it now behaves as an in- 
digenous plant on the sandy and rocky coasts (Harshberger, p. 703), 
it was marked in a list of plants furnished by the Hon. J. H. Darrell 
about forty years ago to the Governor, Sir J. H. Lefroy, as from the 
West Indies (Hemsley in Chall. BoL, I., 61). Unlike many other West 
Indian littoral trees and shrubs it has not been recorded, as far as 
I know, either from the Pacific coasts of America or from the West 
Coast of Africa. Fawcett and Rendle, the most recent authorities, 
restrict it to the eastern side of the New World, and I may add that 
when examining the shore vegetation on both sides of the Panama 
Isthmus, I noticed it only on the north side, as at Colon. 

As a rule where the plant grows it is found in abundance. In the 
West Indies I studied it as a shore tree at St. Croix, in numerous 
places around the coasts of Jamaica, in the Turks Islands, on Grenada 
and on Tobago. It was observed by Millspaugh in the Cayman 
Islands (Plantce Utowance), and its occurrence there is suggestive; 

197 



198 PLANTS, SEEDS, AND CURRENTS 



but it would seem to belong to a late stage in the plant- stocking of 
isolated small islands. From the circumstance that Mr. Lansing 
recorded it from only one of the Florida sand-keys and regarded it 
as introduced, it would not appear to be one of the early plants that 
establish themselves on newly formed islets in these seas. 

In my notes I have only recorded it from four of the islands of the 
Turks Group, namely, on Grand Turk, Long Cay, Cotton Cay, and 
Salt Cay; but where found it is usually abundant. Amongst other 
localities on Grand Turk it grows in quantity in the interior of the 
low-lying level region of the southern half of the island, where on 
a sandy soil it is associated with shrubs or small trees, as the case 
may be, of Bontia daphnoides, Dodoncea viscosa, Euphorbia vaginulata, 
Sophora tomentosa, etc. ; but here, as in other parts of the island, 
it extends in places to the beach. It thrives on the edge of the rocky 
plateau of Long Cay on the leeward side, where it is associated with 
Genipa clusiifolia, the Seven-year Apple. In Cotton Cay it grows in 
dense thickets on the rocky surface of the wind-swept eastern ex- 
tremity of the island, the Seven-year Apple growing under its lee; 
but the constant exposure to the strong trade-wind has compelled 
it to assume a semi-prostrate, straggling habit of growth. Its be- 
haviour in the Turks Islands closely corresponds with that in the 
rest of the Bahamian region, where it grows not only on the sandy 
and rocky shores, but on the dry plains in their rear, and is often 
associated in coastal thickets with Genipa clusiifolia (Harshberger, 
Millspaugh, etc.). 

The fruits are of regular occurrence amongst the smaller drift of 
beaches wherever the plants grow on the coast ; and not infrequently 
they may be found germinating in the drift washed up by the waves, 
together with seedlings derived from the stranded fruits. The 
fallen fruits lie in numbers under the trees lining the beach, and they 
could be easily swept off by the waves at the higher tides. They 
germinate in numbers on the ground beneath the trees, and numerous 
seedlings are to be seen striking into the sandy soil. This inclination 
to rapid germination on the soil would militate against the chances 
of effective dispersal by currents, since seeds that germinate easily 
would, as a rule, be imperfectly protected against the penetration 
of sea-water, and in many cases these fruits, when swept off the 
beaches by the waves, would be in the early stage of germination. 

We come now to the methods of dispersal. The purplish, fleshy 
fruits, 15-20 mm. long, at once suggest the agency of frugivorous 
birds; and it is in this fashion that Hemsley considers the over- 
seas dispersal of the plant may be explained (Chall. Bot. Intro., p. 49). 
In this connection it is noteworthy that Coccoloba laurifolia, one 
of the species that come next to C. uvifera amongst the West Indian 
species with wide ranges, is known in Florida as the Pigeon Plum 
(Fawcett and Rendle). Pigeons would probably be effective agents 
of local dispersal or of inter-island distribution across narrow tracts 
of sea; but it is very doubtful whether they would be effective 
for long ocean traverses that could not be accomplished by a bird 
in a few hours. The defects in structure that unfit the fruit for 
prolonged flotation in the sea, as below described, would also render 



MISCELLANEOUS PLANTS 



199 



it less able to withstand the injurious influence of the digestive 
fluids of a bird for many hours. 

Though in appearance drupaceous, the fruit is described by 
botanists as a nut wholly enclosed in the fleshy accrescent perianth. 
When the fleshy covering has been removed, the nut is seen to con- 
sist of a hard shell containing a kernel enclosing an embryo with 
foliaceous cotyledons in a ruminate albumen. From the history of 
such a structure alone, one would be inclined to doubt the imper- 
meability of the seed-vessel. In this case the nut has a thin crustace- 
ous shell with an outer membranous skin, the shell being wanting 
at the lower end of the fruit, which seems to be a character of the 
family. The gap in the shell is filled up with softer tissue almost 
like a plug; and it is here that the place of weakness as regards 
impermeability to fluids lies. 

Neither the entire fruit in its moist, fleshy coverings, nor the 
freshly removed nut have any floating power; but after the fruit 
has dried up on the ground it acquires buoyancy. It is in this con- 
dition, with the withered outer coverings more or less removed by 
insects and other agencies, that one finds these fruits under the trees, 
the floating power being largely due to the fibro-membranous 
covering investing the shell, and to its association with spongy cellular 
tissue at the lower end. In Jamaica I made three experiments in 
sea- water on the dried fruits gathered from under the trees in different 
localities. In the first experiment half remained afloat after nine 
days. In the two others 50 and 60 per cent, were floating after a fort- 
night's immersion. The respective extreme limits of the floating 
capacity in the three experiments were two weeks, four weeks, and 
seven weeks. But water had always penetrated into the seed-cavity 
of the sunken fruits, and as the fruits soon turned the sea-water 
putrid, it had to be changed daily, results far from indicating any 
special fitness of the fruits for prolonged transport by the currents. 
On the whole I would infer that the penetration of sea-water would 
in the course of a few days or weeks render these fruits quite un- 
suited for effectual distribution over the ocean, and that although 
they would float for a few weeks the germinative capacity would be 
lost, as a rule, in a week or two. 

A practical inference from these results is that Coccoloba uvifera 
could scarcely have reached the Bermudas with the aid of the currents. 
The same objection on structural grounds must be raised to the view 
that the fruits could withstand the influence of the digestive juices 
of a bird during its passage across 800 miles of sea by the shortest 
route to the Bermudas from the Bahamas. The view of the residents 
that the tree has been introduced in later years is probably correct. 

From the foregoing remarks it would appear that a stretch of 
from 100 to 200 miles of sea would be all that either the bird or the 
current could accomplish in aiding the disposal of Coccoloba uvifera. 
Yet the defects of the fruit that limit its capabilities for dispersal 
are generic characters. It is, therefore, scarcely likely that any inland 
species could be better adapted for distribution by birds, whilst in its 
station alone it would lack opportunities for distribution by currents. 
We could not go far wrong if we argued that in Coccoloba uvifera 



200 PLANTS, SEEDS, AND CURRENTS 



we see at their best the capacities of the genus for dispersal. Yet 
measured by the geographical range they have produced effects in 
some inland species (species that could have owed but little to cur- 
rents) which give the inland plants a rank near that of C. uvifera. 
Thus, in Jamaica, out of nineteen species enumerated by Fawcett 
and Rendle eight have been recorded from outside the island. Four 
of them, excluding C. uvifera, are inland, and often mountain, species 
that have a distribution in the West Indies nearly as wide as the 
species just named, and three of the four reach the South American 
continent. It is, therefore, apparent that currents have not endowed 
C. uvifera with a much greater range than is possessed by some 
inland species that could owe nothing to currents; and it is quite 
likely that currents have not been the principal agent in its dispersal. 

Colubrina asiatica, Brongn. 

This littoral shrub is discussed at length in my book on Plant 
Dispersal, and I have there dwelt on the suitability of its buoyant 
seeds for dispersal by currents and on their occurrence in river- and 
beach-drift in the Pacific islands. It is distributed over the warm 
regions of the Old World including the African East Coast; but 
I have found no reference to its occurrence on the West Coast. 
Grisebach gives it as a West Indian plant, but for Jamaica only. 
It should, however, be at once observed that not one of the several 
other authorities consulted (Hemsley, Urban, etc.) mentions it as 
occurring in the West Indies or in the New World, so that we seem 
to have here the same difficulty that, as shown in a subsequent page, 
is presented by Thespesia populnea. 

I found it in fruit growing abundantly beside a beach at Dry 
Harbour on the north coast of Jamaica, where it was associated with 
such characteristic strand trees and shrubs as Coccoloba uvifera, 
Conocarpus erectus, Guilandina bonducella, and Suriana maritima, 
and it was the most frequent of them all. The seeds are indistin- 
guishable from those of the plant in the islands of the Pacific and 
display similar floating powers. 

It may be that the difficulty lies in the species being very rare 
in the tropics of America. The genus, which consists of twelve to 
fifteen known species, is mainly American, a fact that in itself should 
cause us to hesitate in excluding it from the New World, an opinion 
expressed by the writer in his book on Plant Dispersal (p. 563) before 
he visited the West Indies. As tested by him in Fiji, the seeds of this 
species float unharmed in sea-water for many months, and they 
are even better fitted for dispersal by currents than those of many 
other littoral plants. There are, at least, two West Indian species, 
Colubrina ferruginos a and C. reclinata, that are widely spread in that 
region and may be found occasionally in littoral stations (Grisebach, 
Urban, Millspaugh). 

We may add that Colubrina asiatica figures amongst the later 
accessions to the flora of Krakatau, its seeds being derived from the 
neighbouring coasts, where it thrives (Ernst). 



MISCELLANEOUS PLANTS 



201 



CONOCARPUS ERECTUS, L. 

This small tree, which finds its most characteristic station at the 
drier borders of mangrove swamps, has the distribution of the 
American mangrove formation, occurring on the Atlantic and Pacific 
shores of the New World and on the West Coast of Africa. Though 
not one of the mangroves, it is a constant associate of those plants 
and ranges with them throughout the West Indian region, reaching 
north to South Florida on the Atlantic side and to Lower California 
on the Pacific side, and following the mainland south to Ecuador 
on the west and to South Brazil on the east. Its occurrence on the 
Pacific coasts of tropical America is noted by Hemsley (Chall. Bot., 
II., 32). It was observed by myself on the coasts near Panama, 
and also on the shores of Ecuador, where it was also noticed by 
Baron von Eggers. In my book on Plant Dispersal I omitted, on 
page 488, to include it amongst the vegetation of the beach of Jambeli 
Island off the Ecuadorian coast. Millspaugh (Plantce Utowanaz) 
and Harshberger (Phyt. Surv. N. America) give it two localities in 
Lower California, and the former adds Acapulco on the Pacific coast 
of Mexico. Its ability to establish itself on isolated island groups 
is shown by its existence on the Alacran Shoals and the Cayman 
Islands (Millspaugh), and particularly by its occurrence in the 
Bermudas and in the Galapagos Islands. 

Grisebach includes the Marianne Islands (Ladrones) in his list of 
localities. Its occurrence there, though far from impossible, is 
scarcely probable, since it has not been found on any of the archi- 
pelagos in the Pacific excepting the Galapagos Islands. Dr. Rendle 
suggests that there may have been a misreading of the locality, 
since there is in the Herbarium of the British Museum an old specimen 
from Menzies labelled " Marias I 6 , San Bias," off the west coast of 
Mexico (letter cited). 

This species is a most variable one, a behaviour which is evidently 
in response to the different stations in which it is able to thrive, 
since, as shown below, though most typically at home on the borders 
of the mangrove it can accommodate itself to almost every kind 
of station that a coast can offer. It presents all gradations between 
a prostrate trailing shrub and a moderate- sized tree, usually exhibit- 
ing itself as a shrubby tree seven to ten feet high. Grisebach gives 
three varieties, and Millspaugh makes five (Plant. Utow.) ; but doubtless 
there are more. The prostrate forms generally grow on rocks. 

All West Indians know the Button-tree, as they call it. In Ber- 
muda it is termed Button-wood and also Wild Mulberry, from the 
changing colour of its fruits, first white, then reddish, and then 
brown. But its singular roundish fruits are much more like the 
cones of the Alder. In fact, Alnus maritimum was one of its earliest 
botanical names, and Alder-tree is still one of its West Indian names. 
Grisebach also gives, as another of its appellations, Zaragoza Mangrove, 
I suppose from some place on the shores of the Spanish Main. I was 
familiar with it in a number of places, wherever, in fact, the man- 
groves came under my observation, as on St. Croix, Jamaica, Turks 
Islands, Trinidad, Colon, Panama, and the coast of Ecuador, etc. 



202 PLANTS, SEEDS, AND CURRENTS 



Though not a mangrove, it nearly always accompanies the forma- 
tion; yet it can accommodate itself to the dry, sandy beach or to 
the dunes behind, to a muddy flat, and even to a rocky shore. Its 
various stations are well illustrated in Jamaica, where it occurs all 
round the island; but rarely can one dissociate it altogether from 
the surroundings of a mangrove swamp; and in most cases where 
it grows on a sandy beach fronting the coast a mangrove swamp lies 
in the rear of the beach. Though in Jamaica and in other islands 
it may be found growing on a typical dry, sandy beach and on a 
rocky coast, it is around the mangrove borders immediately skirting 
the Avicennia and Laguncularia trees, which form the margin of 
the formation, that it finds its most typical station. In this con- 
nection it often skirts a mangrove swamp on the land side, and 
when it is found on the seaward side it is usually growing on a thin 
strip of sandy beach thrown up by the waves. It is often mixed up 
with Laguncularias and Avicennias on the exposed muddy shores 
of lagoons communicating with the sea. Quite remarkable is its 
frequency in the Black River Morass. Here, though it seemed to 
prefer drier ground, it might be observed two miles inland associated 
with Typhas and tall sedges. Its variety in coastal stations is well 
illustrated in Harshberger's work. But it is to its association with 
the outer mangrove growth of Avicennia nitida and Laguncularia 
racemosa that he chiefly refers, as in the case of Cuba, the Virgin 
Islands area, the Bahamas, and the Californian Peninsula, the 
designation of " Conocarpus-mangrove formation " being employed. 
Yet he speaks of its growing, either prostrate or in dwarfed con- 
dition, on coastal rocks in Bermuda and in the Bahamas; whilst 
in the locality first named it forms thickets on the dunes. 

All its capacities for different stations are displayed in the Turks 
Islands, and in fact they are all illustrated on Grand Turk; but 
the destruction of much of the original extensive mangrove formation 
on the two largest islands, Grand Turk and Salt Cay, has often given 
prominence to stations away from the mangroves. However, in 
the first-named island it is still to be seen associated with Lagun- 
cularias on the land side of the swamps. On the rocky surface of 
Long Cay it thrives in association with Borrichia arborescens ; but 
it adapts itself to the great wind-pressure, to which it is there com- 
monly exposed, by adopting a semi-prostrate habit, like several of 
the shrubs (Tournefortia, Suriana, etc.) on these windward cays. 
Here it clambers over the rocks, and is not more than one or two feet 
in height. This is evidently the variety " procumbens " of Jacquin, 
as given by Grisebach. It thrives on the weather side of Salt Cay, 
both at the borders of the beach and on the dunes behind in the 
company of Tournefortia gnaphalodes and Suriana maritima. It 
may be one of the prevailing small trees or shrubs in the half-stony, 
half-sandy interior of an island like Cotton Cay, where it is in the 
company of the Turk's-head Cactus ; but even here it may be sur- 
mised that its original station was around the central lagoon with the 
mangroves that have since disappeared. This plant is one of the 
marginal associates of the mangrove belt that are able by their greater 
adaptability to survive the destruction of the mangroves at the 



MISCELLANEOUS PLANTS 



203 



hands of man. Its capacity in this respect is exemplified on Gibbs 
Cay, where it grows on the dry sandy slopes of the island. On half 
of the cays that form the Turks Group, namely, on Round Cay, 
Penniston Cay, Pear Cay, Eastern Cay, and Greater Sand Cay, the 
plant was not observed. 

The observations made by Mr. Lansing (and described by Dr. 
Millspaugh) on the Florida sand-keys west of Key West, are of 
interest in this connection, since the method of stocking newly 
formed islands is there illustrated. Out of nineteen keys examined, 
five displayed the plant; and it appears that where it is conspicu- 
ously absent from a group of the keys, as in the Tortugas, this is 
to be attributed to the fact that they lack the mangroves with which 
this tree is usually associated. Yet it is rarely in great quantity on 
any of these Florida sand-keys. Four out of the five possessing it 
displayed only one or two moderate-sized colonies, and it was only 
in the fifth that it was well represented. The station was nearly 
always the same, namely, at the back of the vegetation of the exposed 
sandy part of the islet and bordering the Avicennias that fringed the 
great colonies of Rhizophoras. 

Although it would be wrong, as Schimper also observes (p. 64), 
to number Conocarpus erectus with the mangroves, it would be equally 
wrong to place it with the typical trees and shrubs that line the 
sandy beach. From the standpoint of station it comes between 
the two ; but in the matter of its distribution it has the range of the 
mangroves and accompanies them almost everywhere. When I 
first met with this plant on the coasts of Ecuador and Panama, 
its double station appeared very puzzling. But I found that this 
was recognised by Baron von Eggers, who, whilst studying the 
Ecuadorian strand plants, placed Conocarpus erectus in different 
localities in the mangrove formation and in the sandy-beach flora. 
This is the dilemma in which the plant frequently places the botanist, 
and it is one from which he can free himself by investigating the 
stages of the plant- stocking of newly formed islets in these seas. 
Such an inquiry has been accomplished in the case of the Florida 
sand-keys by Mr. Lansing and Dr. Millspaugh. The last-named 
botanist makes a special association for this locality of the plants 
of the mangrove borders, including Avicennia nitida, Laguncularia 
racemosa, Conocarpus erectus, etc.; and he shows how in the case 
of a young Rhizophora colony, recently established on a newly formed 
sand-key, Conocarpus erectus may take the place of the usual Lagun- 
cularia fringe. 

The small scale-like achenes, which are gathered together in a 
rounded cone-like fruit-head, readily become detached when the 
head dries. They average about 4 mm. across and possess great 
floating power. Although Schimper did not test their buoyant 
capacity, he rightly postulated it from their structure (Ind. Mai. 
Strand Flora, pp. 170, 180), which he compares with that of Ter- 
minalia fruits of the same family. Within the thin, impervious, shell- 
like outer skin there is an extensive development of spongy air- 
bearing tissue, and within this is the seed protected by a hardened 
layer of the endocarp. No part of the fruit or seed has any floating 



204 PLANTS, SEEDS, AND CURRENTS 



power, except the spongy tissue. A number of the achenes were 
placed in sea- water in Jamaica, and after two months they all floated 
buoyantly and contained in some cases sound seeds. Evidently 
they could float for a long period, and could certainly be carried by 
the Equatorial Current across the Atlantic from West Africa to 
Brazil. 

But there is an important point to notice in this connection. 
Although the plant fruits abundantly it oftens matures scarcely 
any seed. One may examine a number of the achenes and find neither 
seed nor stone, or at all events only in a few cases, as in a sample 
from the Turks Islands, where only 3 or 4 per cent, contained a seed. 
This was remarked by Schimper (p. 171), and he quotes Bentham 
and Hooker to the effect that this is a frequent phenomenon. But 
I should imagine that it rarely happens that one meets with the 
experience of Schimper, who found every fruit examined to be seed- 
less. Thus, whilst writing these lines, I have examined a sample 
of fruits from Jamaica, and find about 10 per cent, seeded. As a 
set-off against this defect in seeding one must place the abundant 
fruiting of the plant. Taking the average number of fruit-heads on 
a panicle at fifteen, and the average number of achenes per head 
at thirty-three or thirty-four, then each panicle would contain 500 
achenes and, taking the proportion of seeded fruits at 4 per cent., 
twenty seeds. Each small tree must develop a large number of 
these panicles in a season. Suppose we place them at fifty, which 
is probably below rather than above the average, then each plant 
would mature a thousand seeds, which I imagine would be as many 
as an ordinary Terminalia tree would mature in a single season. 

Schimper undoubtedly regarded this plant as dispersed by the 
currents, and the same position was taken by Hemsley in his discus- 
sion of the Bermudian flora (Chall. Bot., L, 48). Millspaugh, however, 
in his paper on the Florida sand-keys, regarded it as probably distri- 
buted by birds. I think, however, that a good case has been made 
for the currents. It may be noted in conclusion that there is every 
reason for believing that it is truly indigenous, and that it reached 
Bermuda with other West Indian plants characterised by Mills- 
paugh as belonging to the association of the mangrove border. 
Hemsley recognises this plant as probably one of the four that can 
be identified from the description of Jourdan, who accompanied 
the expedition of Sir George Sommers that was wrecked on the 
Bermudas in 1609. It is noteworthy that three out of these four 
early Bermudian plants, namely the Prickly Pear (Opuntia), the 
Juniper (J. bermudiana), and the Palmito (Sabal blackburniana) had 
evidently been established there through the agency of frugivorous 
birds (Chall Bot., I., 49; II., 3). 



Crudya spicata, W. 

In its range the leguminous genus Crudya presents most of the 
difficulties offered by Chrysobalanus (p. 193). Out of fourteen 
known species all are American with the exception of one African 



MISCELLANEOUS PLANTS 



205 



and one Philippine species, the most important difference between 
the two genera being that Crudya, unlike the other genus, has no 
species common to both the American and African sides of the 
tropical Atlantic. This difference is associated with the fact that 
when we compare the two species of these genera that are most 
likely to be dispersed by the currents, Chrysobalanus icaco of the 
seashore and Crudya spicaia of the fresh-water morass of the lower 
levels, the only one that could perform an ocean traverse through 
the agency of its floating fruits or seeds is Chrysobalanus icaco, the 
West African shore plant. But even here the traverse of the ocean 
is restricted by the limited floating capacities of the fruit to the 
passage in the Main Equatorial Current from the Gulf of Guinea to 
Brazil. 

The distribution in the West Indies of the trees of the genus 
Crudya, as indicated by Grisebach, is very interesting and provokes 
inquiry. Three species are named, of which two are described as 
frequenting swampy districts; whilst the station of the third is not 
mentioned. All occur in the Guianas, one of them (the species 
under consideration) being found also in Jamaica and the other two 
also in Trinidad. 

It is with the species at home both in Jamaica and Guiana, namely, 
Crudya spicata, that we are specially concerned, though it is highly 
probable that the general features of its behaviour will be reproduced 
by the other two species. This tree raises all the questions presented 
by Symphonia globulij era (p. 243) and Grias cauliflora (p. 211). It 
is especially comparable with the first named, since both occur in 
Guiana. All three plants are trees of the riverside. In all three 
cases the trees add their fruits or seeds to the floating river-drift, 
and in all three cases the floating fruit or seed is usually found in 
the germinating condition. In not one of these three trees do the 
means of dispersal explain the presence of the same, or, as in the 
case of Grias, of closely allied species in the large West Indian islands 
and in the South American mainland. All three species are in the 
same sense "difficult" plants. They are all of the greatest signifi- 
cance to the student of distribution, and in all of them he is forced 
to admit that " means of dispersal " do not explain " range." 

Crudya spicata, according to Grisebach, flourishes in the great 
morass of Westmoreland in Jamaica, and Britton has more recently 
referred to it in the same locality (Harshberger, p. 678). I found it 
in that district on the banks of the Cabarita River in association 
with Grias cauliflora. It also came under my notice on the banks 
of the Black River near Lacovia. The flat ligneous legume, which 
is about inches long and tardily dehiscent, contains one or two 
large seeds which possess only thin, pervious, membranous coverings 
that afford no protection against drying and but little against the 
penetration of water. The pods are to be seen afloat in the river- 
drift as well as the seeds ; the last owing their buoyancy to a large 
central cavity between the flat cotyledons, the embryo itself having 
no floating power. When the seeds occur in the floating drift, they 
look rather like those of Entada scandens, and the Black River people 
give them the same name of " Cacoon " ; but they are readily dis- 



206 PLANTS, SEEDS, AND CURRENTS 



tinguished by their soft coverings. The floating pods are much 
less frequent. 

Quite 80 per cent, of the seeds afloat in the Black River drift were 
in a germinating condition, a result not to be surprised at when we 
reflect on the unprotected state of the seed. The germinating seeds 
when carried down to the sea would soon be destroyed by the salt 
water; whilst the few that had not begun to germinate would, on 
account of their unprotected character, meet the same fate. The 
buoyant capacity would, of course, be limited under any condition, 
and the tendency of the seeds to germinate afloat would render them 
quite ineffective for purposes of dispersal by currents. I did not 
learn how the seeds liberated themselves from the pod, whether 
on the tree or in the river. But it seems probable that in the last 
case the pod takes up water, and that this leads to its rupture through 
the swelling of the seeds. This appears to be indicated by the fact 
that the seeds afloat in the river are too large for the pod as it grows 
on the tree. The germinating seeds are thrown up in numbers on 
the beaches near the Black River estuary, and shrivel up in the sun. 
The pods were not to be found in the beach-drift, and evidently they 
do not reach the sea. 

Seeds of a species of Crudya are brought down by the Orinoco and 
deposited in the germinating state with much other drift on the south 
shore of Trinidad. 

Some matters have still to be investigated relating to Crudya 
spicata; but enough has been said to show that it possesses no 
effective means for overseas dispersal. We cannot look there for 
an explanation of its range. 

DODONiEA VISCOSA, L. 

This plant is discussed at length in my work on Plant Dispersal 
(p. 338, etc.). Here, as there, Bentham is followed in the inclusion 
within this species of nearly all the extra- Australian forms. In the 
West Indies I renewed my acquaintance with this cosmopolitan plant, 
more especially in Jamaica and the Turks Islands. The form that 
I experimented on in Jamaica was Dodoncea burmanni, DC; but, 
as Grisebach observes, both this form and that of D. viscosa proper 
grow on the seashore in that island. Since they occupy the same 
stations and accompany each other over most of the warm portions 
of the globe, both as littoral and inland plants, the facts of distribu- 
tion would in this respect go to support Bentham' s view of the com- 
prehensive nature of the species. 

The form above named grows in Jamaica among the vegetation 
bordering the beach and on the drier mud-flats and behind the 
mangrove fringe of the salt-water lagoons in the Black River district, 
where it is associated with Conocarpus erectus, Coccoloba uvifera, 
etc. Millspaugh speaks of Dodoncea viscosa growing on the sandy 
beach at Grand Cayman (Plantce Utowance), and Harshberger mentions 
it as a dune plant in Bermuda (p. 703). 

The dark round seeds, 2-5 to 3 mm. in diameter, float in sea- 
water, their buoyancy being due to the unfilled space in the seed- 



MISCELLANEOUS PLANTS 



207 



cavity, neither coats nor kernel having independent floating power. 
Of some tested in Jamaica half were afloat after six and a half weeks 
in sea- water, most of them with sound kernels. Schimper found 
that seeds of D. viscosa floated from ten to sixty days (p. 165). 

In the Turks Islands this plant only came under my notice on 
Grand Turk. There, in the company of Sophora tomentosa and of 
plants peculiar to this region, it thrives in the sandy interior of the 
southern part of the island, but does not appear on the beach. 

Dodoncea offers in its distribution much the same problem that 
is presented by Cassytha and Sccevola as discussed in other pages of 
this work. Here we have three genera, in great part Australian, 
which are, however, represented over the warm regions of the globe 
by one or two species typically littoral in their habit, but able in 
the case of those of the first two genera to accompany xerophytic 
plants far inland. Here we have a clue to distribution, which if 
thoroughly investigated might lead to rich results, though it would 
require many years of travel and research. It can only be said here 
that my later inquiries in the West Indies go to confirm the general 
inference given on page 341 of my previous work, namely, that in 
the case of Dodoncea viscosa currents alone could not account for its 
distribution in oceanic islands like Hawaii, and that if we placed 
the agencies of dispersal in their order of effectiveness they would 
be, first, granivorous birds, then the currents, and lastly man. 

It may here be observed that this plant was found established 
on Krakatau in 1906. more than twenty years after the great eruption. 
It was also noticed on the neighbouring coast of Sumatra (Ernst, 
pp. 17, 40). As one of the plants of the old dunes it is found near 
the coast all over New Zealand, and has also reached the Chatham 
Islands (Cockayne's Report on the Dune Areas of New Zealand, 1911, 
pp. 30, 33). 

ECASTAPHYLLUM BROWNEI, PerS. 

This small leguminous shore tree, which is not only widely dis- 
tributed in the tropics on the American side of the Atlantic, but 
occurs also on the West Coast of Africa, is one of the commonest 
plants bordering the beach in these regions. It extends from 
South Florida through the West Indies to Southern Brazil, and is 
found on both the Atlantic and Pacific shores of Central America. 
It is one of the plants that De Candolle regarded as at home in 
America, but as naturalised in Africa. In West Africa, however, 
it behaves as an indigenous tree ; and when we read in Dr. Vogel's 
journal quoted in Hooker's Niger Flora, that with Chrysobalanus 
icaco it forms the jungle that clothes the strand near the mouth of 
the River Nun, we are reading of the association of two typical West 
Indian shore trees or shrubs in tropical West Africa. Both of them 
were viewed by De Candolle as American plants naturalised in Africa 
{Giogr. Botan., p. 792) ; yet both of them would be quite unfitted, 
as regards their fruits, to accomplish in an effective state the long 
drift involved in the passage from the American to the African con- 
tinent by the Gulf Stream route. The only Atlantic traverse avail- 



208 PLANTS, SEEDS, AND CURRENTS 



able for them would be the shortest, namely, from the West African 
coast to Brazil in the Main Equatorial Current. 

I was familiar with this shore tree in different places, and especially 
in Jamaica and at Colon; and its pods were a frequent constituent 
of the drift on the beaches of those localities. The pods were amongst 
the collection of beach-drift made by Morris in Jamaica, their seeds 
appearing quite sound (Chall. BoL, IV., 300). When, however, we 
examine their capacity for trans-oceanic dispersal by currents, we 
find it insufficient. They are too fragile for withstanding the buffet- 
ing involved in dispersal by ocean currents for more than a few weeks ; 
and they soon begin to decay and to admit water, against which the 
thin coverings of the enclosed seed could afford no protection. The 
currents have been effective agents in establishing many of the West 
Indian plants in Bermuda ; but this tree is not one of them. This 
is very suggestive, because almost all of them are well suited for 
dispersal by currents ; and the inference is that, though the currents 
could carry these pods unharmed from island to island in the West 
Indies, they have not been able to carry them in this condition to 
the Bermudas. The agency of the drifting log could scarcely be 
invoked, since, as we shall see, the question is not so much one of 
buoyancy as of the inability of the pod to preserve the seed from 
injury through the penetration of sea- water, and this danger would 
still threaten a pod in the crevice of a drifting log. It is significant 
that these pods did not come under my notice in the stranded drift 
of the Turks Islands ; nor does the plant grow in the group. 

The legume is a single-seeded, flat, somewhat oblique, oblong pod, 
about an inch in length. It floats buoyantly in the dry state; but 
it owes its buoyancy entirely to the air-bearing tissue in the walls 
of the pericarp, the seed possessing no floating power and filling 
the seed-cavity. But for purposes of prolonged oceanic transport 
the pod is too fragile, and is not sufficiently impervious to water, 
the thin seed-coverings also offering no protection against sea-water. 
In appearance the pod does not seem much better fitted for with- 
standing prolonged sea- water flotation than the dried pod of Pisum 
sativum. Under the quiet conditions of two experiments made in 
Jamaica, the pods showed no tendency to sink after a month's 
flotation, but in some cases water had penetrated and the seed was 
decaying, and there was little to indicate that the seed would retain 
its germinative capacity after the pod had been exposed for more 
than a few weeks to the " rough-and-tumble " of oceanic transport. 

Erythrina 

Reference may first be made to the supposed seeds of this genus 
thrown up on the Orkney Islands and on the coasts of Scandinavia, 
which are referred to in Chapter II. (pp. 23, 26). The Orkney drift 
seed figured by the elder Wallace is evidently an Erythrina seed, and 
the " Bent-stones " (Buesteen) of the early describers of Scandinavian 
foreign drift may probably be placed here. Tonning, a pupil of 
Linnaeus, includes Piscidia erythrina amongst the plants contributing 
to the Scandinavian drift (Amoenitates Academicce, VII., 477, as quoted 



MISCELLANEOUS PLANTS 



209 



by Hemsley in Chall. Bot., IV., 278), and Gumprecht, employing the 
same reference in page 420 of his paper, observes that Tonning 
referred the Scandinavian " Buesteen " to Piscidia erythrina. This 
leguminous tree, as shown below, is not at all likely to have furnished 
the " Bent-stone " seeds of the Scandinavian beach-drift; and it is 
noteworthy that Sernander, the most recent writer on this subject, 
who was doubtless guided by Lindman, excludes it from his list of 
Tonning' s identifications. 

Piscidia erythrina, L., is a West Indian tree, the seeds of which, 
as described in Grisebach's work, are one-third of an inch long, 
black, sub-compressed, and transversely oblong. They evidently 
would not be described as " Bent-stones " or " Curved- stones " ; 
and it is very unlikely that they possess buoyancy. Though the 
tree is common in the West Indies, its seeds have never been 
recorded from the beach-drift. 

There is, however, abundant evidence to show that the seeds of 
littoral species of Erythrina, to which the name of Bent-stone would 
apply, are dispersed by currents in the Indian and Pacific Oceans, 
and I have dealt at length with the matter in my book on Plant 
Dispersal (pp. 141, 435, 437-8, 489, 577). In those regions they 
figure in stranded beach-drift and in the floating drift of rivers. In 
the West Indies the species with buoyant seeds do not seem common 
enough to enable them to figure in the beach-drift. But on the 
South American mainland, as illustrated in the case of the estuaries 
and beaches of Ecuador (Ibid., p. 489), Erythrina seeds are abundant 
in floating and stranded drift, and may be observed miles out at sea 
off the river mouths. A systematic inquiry into the buoyancy of 
the seeds of the New World species of the genus is needed. I experi- 
mented on those of Erythrina velutina and E. corallodendron, neither 
of which are littoral species. In the first case most of the seeds have 
buoyant kernels, two-thirds floating in fresh-water and nine-tenths 
in sea-water. Of four seeds that floated in sea-water three were 
afloat after a month. The seeds of Erythrina corallodendron displayed 
no floating power and possess non-buoyant kernels. 

Genipa clusiifolia, Gr. (Seven-year Apple) 

This remarkable maritime shrub, which attains a height of from 
four to six feet in the Turks Islands, has a limited distribution, being 
restricted according to the authorities to Cuba, the Bahamas, and 
South Florida, though its presence in Hispaniola would seem probable. 
Although it is well distributed over the Bahamian region, extending 
to the extreme south-easterly sub-groups, the Inaguas, the Caicos 
Islands, and the Turks Islands, it has not been recorded from Ber- 
muda. Its absence from the Florida sand-keys west of Key West 
is of interest, since it grows on the Florida coast ; whilst this and the 
other negative features of its range go to suggest a small capacity 
for dispersal by currents. It belongs to a genus that is confined 
to the warm regions of the New World. 

Yet there is much to attract the student of dispersal in the " Seven- 
year Apple," the name by which it is known all over the Bahamian 



210 PLANTS, SEEDS, AND CURRENTS 



region. The origin of the name is obscure, and it promises to remain 
in obscurity, since Catesby, who was in these islands about 1725, 
remarks in his work on the natural history of this region (I., 59) : 
" I know not for what Reason the Inhabitants of the Bahama Islands 
call it the Seven Years Apple." In this connection it should be noted 
that in January and February 1911, during my sojourn in the Turks 
Islands, it was in flower and unripe fruit. Catesby states that it 
ripens its fruit in seven or eight months. One may notice that the 
name of "Seven-year Vine" is according to Grisebach applied in 
the West Indies to Ipomoea tuberosa, a widely distributed plant with 
an inedible tuber, dealt with in Chapter VI. 

I found Genipa clusiifolia growing on four of the ten islands of the 
Turks Group, namely, Grand Turk, Long Cay, Cotton Cay, and 
Greater Sand Cay. On Grand Turk individual plants grew amongst 
the rock masses at the foot of the bluff that rises in the rear of the 
broad beach at the southern extremity of the island. It also grew 
on rocky ground in the interior of the island in different localities, 
as on the low hills around the North Wells; but I never noticed it 
growing in colonies, as in some of the smaller cays. It composed 
great thickets on the rocky surface of Long Cay on the lee or south- 
west side, being associated with Coccoloba uvifera ; and it extended 
to the edge of the low cliffs that form the border of the island. On 
the eastern or weather end of Cotton Cay a few plants were associated 
under similar soil conditions with dense thickets of Coccoloba uvifera 
and a quantity of Phyllanthus falcatus. It occurred probably on 
other parts of this island. On Greater Sand Cay it was one of the 
most characteristic plants, especially in the northern half, growing 
in colonies over the sandy and rocky surface, but not coming down 
to the beaches. In all these localities the plant in the early part of 
1911 was in flower and unripe fruit, the fruiting stage being most 
pronounced. 

This plant is truly littoral in its station. In Cuba, as remarked 
by Grisebach, it grows on maritime rocks. Millspaugh writes that 
it occurred on coastal rocks on all the Bahamian islands visited 
(Pramunc. Baham.). Harshberger includes it in the Bahamian 
strand formation, assigning it a station not only on the coastal 
rocks, but also on the sandy ridges and mounds behind the Tourne- 
fortia-Suriana association. He writes that it is an element of the 
sandy strand formaton of South Florida (Trans. Wagner Inst. Phila- 
delphia, Oct. 1914, p. 70; Phyt. Surv. N. America, pp. 690, 692). 

The fruit is an egg-shaped berry, 2 J to 3 inches long, yellowish and 
hard in the unripe condition, but reddening as it approaches maturity. 
When ripe, as Catesby tells us, it is pulpy and has the consistence of 
a mellow pear. (The fruits at the time of my visit to the Turks 
Islands were full-sized, but still hard.) It possesses a thick rind 
and a large number of dark-brown, flat crustaceous seeds, one-fifth of 
an inch (5 mm.) long and lying horizontally in a relatively scanty 
pulp. It is a curious fact that I never observed either withered 
fruits on the plant or fallen fruits on the ground. It is probable 
that they are much appreciated by the large iguanas found on some 
of the cays ; and it is noteworthy that the two islands most frequented 



MISCELLANEOUS PLANTS 



211 



by jthese reptiles, Long Cay and Greater Sand Cay, were the two on 
which the plant was observed growing in greatest abundance. 

To my surprise the fruits approaching maturity, though still hard, 
floated buoyantly, the floating power lying in the thick rind or 
pericarp, which is protected by a tough skin. Four of them were 
placed in sea-water, where they floated for three weeks, when they 
becran to rot and the seeds commenced to fall out and sank. If we 
allow for the fruits floating in fragments a few days longer, it is prob- 
able that a month would represent the limit of the floating capacity. 
One such fragment I found washed up on the beach of Grand Turk. 
However, the hard fruits could only be torn off from the plant during 
hurricanes. The mature soft fruit, if it did not sink at once, would 
break up afloat in a few days. The plant seems to be quite useless, 
and could owe but little directly to human agency in its dispersal. 
However, the present islanders carry the living iguanas from island 
to island for purposes of food, a practice probably followed by the 
Caribs, and any of the hard seeds in the stomachs of these reptiles 
would thus be distributed. 

Grias cauliflora (Anchovy Pear tree) 

Known as the Anchovy Pear tree, Grias cauliflora is one of the 
most picturesque trees in the river scenery of Jamaica; and from 
many points of view it is amongst the most interesting, its " cauli- 
flory ?? at once attracting attention. The genus was originally 
established by Linnaeus from this Jamaican tree, as first described 
under its popular name by Sloane in his book on the natural history 
of that island (Vol. II., p. 123, etc. ; table 216). Unfortunately Miers, 
when he wrote his monograph on the Lecythidacece (Trans. Linn. 
Soc, XXX., 1875), to which the genus belongs, was not acquainted 
with the fruit. Yet the fruit, as will be shown, plays an important 
part in the distribution of Grias cauliflora along the same river 
system. 

In Jamaica it grows, as Sloane observes, by the riverside. It may 
be noticed both on the banks and in the shallows and even on the 
slopes of waterfalls. As observed by me, it thrives on the banks of 
the Black River and of the Cabarita River above the mangroves 
and on the sides of streams in the district south-east of Negril, as 
well as in similar stations on the north side of the island. At the 
Roaring River Falls it grows not only at the brink of the falls, but 
in the wash below them, as well as half-way down their face, where 
the fruits have caught in the crevices of the calcareous tufa en- 
crusting the declivities. Harshberger (p. 678), when in this locality, 
noted that the trees grew directly in the water, their seeds having 
germinated in the tufa. It may here be remarked that Sloane's 
statement that the Spaniards used to eat the pickled fruits as a 
substitute for mangoes may perhaps supply an explanation of the 
popular name of the tree. The mature fruits would be singularly 
unfitted for food, and doubtless the young fruits were thus employed. 

Grisebach gives Jamaica as its only habitat in the West Indies, 
and mentions no other West Indian species. I have not been able 



212 PLANTS, SEEDS, AND CURRENTS 



to find a reference to it in any other island, though Sloane states that 
it grows all over the West Indies. From the fact that the fruits, 
which possess considerable floating powers, are significantly absent 
from the drift heaped up on the beaches of the Turks Islands, it 
would seem that the tree does not grow in the islands which are 
the source of much of this drift, namely, San Domingo, Porto Rico, 
and the neighbouring Leeward Islands. Whilst the fruits are 
characteristic of the drift of the Jamaican beaches, being thrown 
back on the coast after being brought down by the rivers, as in the 
vicinity of the mouths of the Black River, the Cabarita, and the 
White River, they did not come under my notice in the beach-drift 
of Grenada, Tobago, and Trinidad. They would, therefore, appear 
to be unrepresented in the drift of the Orinoco and the Amazon, 
since it is stranded in quantity on those islands ; and one may note in 
passing that Hart does not mention the tree in his " Herbarium List " 
of the Trinidad flora. It is, however, shown below that the same tree 
evidently exists on the upper reaches of the Guayas River in Ecuador, 
and that an unidentified species of the genus grows in quantities near 
rivers on the lower eastern slopes of the Ecuadorian Andes. 

Whilst its limited distribution in the West Indies may be partly 
due to the little power of preserving the germinative capacity of the 
seed in the floating fruit, a matter discussed below, it is evident that 
questions quite apart from those relating to means of dispersal are 
here raised. According to the Index Kewensis (up to 1905) the genus 
holds four species referred respectively to Peru, Panama, the West 
Indies, and Guiana. But a mere list of species with their habitats 
conveys no notion of the role plants of this genus play in tropical 
South America. It would appear that these trees are especially 
at home on the lower slopes of the Equatorial Andes on the Pacific 
and Atlantic sides, as well as along the upper reaches of the rivers in 
that region. Spruce found Grias trees in the Chimborazo forests 
extending up to 3500 feet above the sea (Notes of a Botanist on the 
Amazon and Andes, II., 286; 1908). Mr. A. R. Wallace, who edited 
Spruce's book nearly half a century after the traveller returned from 
South America, subsequently sent to the Kew Bulletin (1909, p. 216) 
some additional notes made by Spruce on the riverside vegetation 
of the Upper Amazon. We there learn that a species of Grias almost 
entirely composed the forest in places on the Pastasa River, a tribu- 
tary of the Maranon branch of the Amazon, on the lower eastern slopes 
of the Ecuadorian Andes. The specific identity was not determined 
in these cases ; but I may add that on comparing some of my Jamaican 
specimens of the fruit of Grias cauliflora with fruits gathered by me 
some years before from the floating drift of the Guayaquil River in 
Ecuador, the two kinds could not be distinguished from each other. 
These floating fruits formed a feature in the drift of this Ecuadorian 
estuary, and evidently were derived from the upper reaches of the 
river. Specimens of them sent by me to the Kew Museum have been 
labelled Grias cauliflora by those in charge. 

Looking at the foregoing facts of distribution, it seems fair to 
assume that this genus was once far more widely spread over the 
West Indies than it is at present. It is doubtless a remnant of a 



MISCELLANEOUS PLANTS 



213 



flora that once held the region, now occupied by the Caribbean Sea, 
which united the Greater Antilles with Central and South America 
(vide Harshberger, p. 307). From the data given below with respect 
to the fruits of Grias cauliflora, it would seem that the genus is quite 
unsuited for dispersal by marine currents. 

The fruits readily get into the floating drift of rivers, on the banks 
of which the tree so often finds its station. They are elliptical, 
3 to 3 J inches long, possess eight prominent ribs, and contain a fleshy 
though tough seed, 1J to 2 inches in length, which is merely, as in 
Barringtonia, a gigantic hypocotyl, the cotyledons being absent or 
inconspicuous. The buoyancy of the fruit is entirely due to the 
husky fibro-ligneous pericarp and to its air-bearing tissue, the seed 
sinking in water. But though the fruit can evidently float for 
months, it is far from impervious to water. It soon loses in the 
floating river-drift the outer thin skin of the living fruit, and water 
enters freely into the seed-cavity, the membranes investing the seed 
affording little or no protection. As a result, the floating fruits 
soon begin to germinate in river-drift. Thus, in one of my ascents 
of the Black River in January, I estimated that 50 per cent, of the 
floating fruits were germinating, showing roots up to three inches in 
length. Forty per cent, had been so long in the water that the seed 
had disappeared through decay or was in a decaying condition, and 
there can be little doubt that most of these had originally germinated. 
Ten per cent, had more or less fresh seeds that had not yet begun to 
sprout. When the floating fruit reaches the coast, the sea-water 
kills the seed, whether or not in the germinating state. 

Although when stranded on a sea-coast these buoyant fruits would 
either be empty or would carry a dead or decaying seed, it cannot 
be doubted that if the trees were at all frequent on the large island 
of Hispaniola, about 100 miles away, their fruits would be washed 
up on the beaches of the Turks Islands. Their absence from the 
drift of these islands indicates the absence or rarity of the tree on 
Hispaniola, as well as on Porto Rico and in the neighbouring Lesser 
Antilles, islands which collectively represent the main source of the 
foreign beach-drift of the Turks Islands. This implication goes to 
support the view that Grias cauliflora occupies a very restricted area 
in the West Indies, an area which it has been unable to extend 
through the agency of the currents. The species would thus appear 
to be on the road to extinction in the West Indian region. 

Yet the fruits, useless as they are for the purposes of oversea 
distribution, are frequent on the beaches for several miles east and 
west of the Black River estuary in Jamaica. They are also to be 
found amongst the shore-drift near estuaries on other parts of the 
coast of this island, wherever the tree thrives at the riverside. 
Thus, they were noticed near the mouth of the Cabarita River at 
the south-west corner of the island and near the estuary of the White 
River on the north side. As they lie on the beaches several still show 
the protruding rootlets of the germinating seed, but in a shrivelled 
state. Several also are empty, or display a seed far decayed. 

But when, as not infrequently happens, the seed is still entire, it 
undergoes a very curious change as it lies within the fruit on the 



214 PLANTS, SEEDS, AND CURRENTS 



beach fully exposed to the sun and weather. The tough, fleshy 
seed of the living fruit here dries up and hardens until it has the 
consistence and appearance of a stone, a change affecting both the 
seed that has germinated and the seed that has not. In this new 
state, however, the seed retains the normal amount of hygroscopic 
water, such as we would look for in dead vegetable substances of the 
same nature. As is pointed out in my book on Seeds and Fruits 
(p. 232), it loses about 12 per cent, of water when exposed to a tem- 
perature of 100° C, and there is no indication of its having assumed 
the characters of inorganic substances. 

On some beaches most of the stranded fruits contained these hard, 
stone-like seeds. Thus, on a beach in the Black River district about 
25 per cent, possessed either no seeds or seeds far advanced in decay, 
the rest having dead seeds that had experienced the stony induration 
above described. Placed in a collection of fossil fruits from some 
clay formation, one of these oblong, indurated seeds of Grias cauliflora 
might pass as a fossil fruit, particularly when a longitudinal section 
had been made so as to expose the central axis in relief. At all events, 
they might be readily fossilised in ordinary fresh-water deposits, 
and it is quite likely that some puzzling organic forms in the old plant- 
beds may be petrified seeds which, as in the Barringtonice and 
Lecythidece, are merely greatly enlarged hypocotyls. 

Hibiscus elatus, Sw. (Paritium elatum, G. Don) and Hibiscus 
tiliaceus, L. (Paritium tiliaceum, A. Juss.) 

At some future time I may publish my notes on the different 
species of the Hibiscece from the distribution standpoint, a subject 
already partially dealt with in my work on Plant Dispersal. Here 
I will endeavour to bring my methods to bear on the elucidation 
of the causes of the great difference in range between these two 
allied species, one (H. elatus) confined to a relatively small area in 
the New World, the other (H. tiliaceus) occurring all around the 
tropical zone. Hibiscus tiliaceus is a species with which I have 
long been familiar in many parts of its range — on the Atlantic and 
Pacific sides of America, in various Pacific islands, in the Malayan 
region, and in the Keeling Islands in the Indian Ocean. 

On making the acquaintance of Hibiscus elatus in Jamaica I recog- 
nised that it gave me an opportunity of comparing two allied species 
(both of them placed under Paritium) of widely different ranges, and 
I asked myself whether this great contrast in range could be asso- 
ciated with differences in behaviour, as regards station, means of 
dispersal, etc., or whether, assuming the intervention of man, it was 
connected with the utility of one tree and the uselessness of the 
other. Obviously here was an opportunity of making a flank attack 
on the problems concerned with H. tiliaceus. It soon appeared, 
however, that the determining factor was concerned neither with 
man nor with means of dispersal, but with differences of station, and 
that the same point was raised, to which my attention had been 
drawn in various genera in the Pacific islands, namely, that in a genus 
possessing littoral and inland species, the first had often very wide 



MISCELLANEOUS PLANTS 



215 



ranges and the second very restricted ones {Plant Dispersal, Chaps. 
XIV., XV.). 

In Jamaica, like H. tiliaceus its sister species, H. elatus is known 
as the Mahoe; but although when of small size it might easily be 
taken for the other species without close inspection, it is typically 
a much more imposing tree. Whilst that of H. tiliaceus is usually 
from ten to fifteen feet in height, that of H . elatus is large and spread- 
ing and often between thirty and forty feet high. It is also dis- 
tinguished by its larger flowers, its hairy seeds, and by its deciduous 
involucel and calyx, the loss of which gives the fruits a very 
characteristic appearance on the tree. Its distribution in the West 
Indies is evidently restricted, Grisebach giving only Jamaica and 
Cuba. 

But its station is of peculiar interest, since in the comparison of 
the two species from the standpoint of distribution it seems to offer 
the only determining difference that one can connect with the great 
contrast between the ranges of the two trees. In Cuba its habit 
is evidently hygrophilous, since Harshberger quotes Fernow (p. 677) 
as including it amongst the characteristic trees of the " wet " forests 
on the weather slopes of the island, where " the atmosphere is nearly 
saturated with moisture." Here it is associated with Calophyllum 
calaba, a tall tree common in the mountain forests of the West Indies. 
Grisebach merely states that in Jamaica it frequents the lower hills 
and plains of the interior districts. I found it growing in young wood 
in the Moneague district about a thousand feet above the sea and 
within the zone of heavy rainfall. It came under my notice on the 
banks of the Black River above Lacovia, where the river traverses 
the foot-hills, the slopes being well wooded to the waterside with tall 
trees of Cassia, Ficus, etc. It also extends for some distance on the 
river border below Lacovia, where the river traverses the Great 
Morass, a region of fresh-water swamps, where it accompanies on 
the riverside Grias cauliflora, the Anchovy Pear tree. 

In Jamaica this is not a tree that finds a station amongst the 
strand flora or with the xerophilous plants of the dry coastal plains. 
In these respects it differs fundamentally from Hibiscus tiliaceus, 
growing as it does under much moister atmospheric conditions in 
upland regions and descending along the riverside where the wooded 
hill-slopes reach the lowlands. It is probable that the station at 
the riverside is connected with the buoyancy in sea-water of the 
seeds, a principle enunciated in my previous work. The seeds, as I 
found, are able to float unharmed for at least several weeks, though 
their floating capacity is probably less than that of the seeds of 
H. tiliaceus, where my experiments, as well as those of Schimper 
(Ind. Mai. Strand Flora, p. 165), indicate a floating capacity of from 
four to six months and more. 

Hibiscus elatus yields the celebrated Cuba bast, and is cultivated 
for that commodity. In this respect it offers another point of resem- 
blance to H. tiliaceus, which in its bast was one of the most useful 
trees for the Pacific islander, supplying the materials for cordage, 
nets, native cloth, etc. Since both possess seeds that could be 
dispersed by currents, and since both would be regarded as useful 



216 PLANTS, SEEDS, AND CURRENTS 



trees, it would not appear that either man or the currents would of 
themselves alone determine the great difference in range. I have 
shown in my previous work that capacity for dispersal by currents 
is not of itself sufficient to give a plant a wide range. Behind this 
capacity must lie a littoral station, and behind that again a xerophilous 
habit. Whilst H. tiliaceus is to be placed with the xerophytes of 
the sea border and of the dry inland plains, H . elatus associates with 
the hygrophytes of the wet woods of the interior. Though both 
may be found at the riverside, the first is confined to estuaries 
within tidal influence, whilst the last frequents the higher reaches 
where the river traverses wooded districts and where mixture with 
salt water would not be expected to occur. 

These two allied species further illustrate the principle, already 
alluded to, that whilst coast plants are often spread over a wide area 
of the globe, inland plants of the same genus are restricted to a 
limited region. Mere capacity for dispersal by currents would not 
bring this about unless it concurred with a littoral station. The 
seeds of Hibiscus elatus, after being carried down by a river from 
the interior of an island to the sea, would find no suitable station 
when stranded by the currents on some neighbouring coast. It is 
the station at the coast that enables the seeds of H. tiliaceus to 
establish the plant when transported to another shore. 

I come now to deal more especially with Hibiscus tiliaceus. This 
is one of the " problem " plants of distribution, which, like Acacia 
farnesiana, Thespesia populnea, etc., are found all round the tropics 
and are as a rule littoral in station. With this tree, as with Thespesia 
populnea, it is the littoral station that determines the effectiveness 
of the currents in dispersing the seeds. But other agencies of dispersal 
cannot be excluded, such as the influence of man, and, for local dis- 
tribution, the intervention of birds and other animals. Many details 
of its station, distribution, and dispersal in the Pacific are given 
in my book on Plant Dispersal. Here I will mainly confine my 
remarks to its behaviour in the West Indies. 

This was one of the plants in which De Candolle took special 
interest. In his work on geographical botany (p. 769), whilst recog- 
nising man's agency in its dispersal, he suspects that currents were 
originally effective agents in its distribution, and perhaps at a very 
ancient date. Not knowing whether it was most common in the 
east or in the west, that is, in the tropics of the Indian Archipelago 
or in those of America, he does not at first assign it a home in either 
hemisphere. However, in a later page (p. 792) he places it with 
Acacia farnesiana amongst plants spread by the currents, but prob- 
ably American and naturalised in Asia and Africa. I scarcely think 
that a purely American origin can be sustained. It doubtless attained 
its present distribution ages ago, and may have witnessed the emerg- 
ence of primeval man around the tropics of the globe. Under such 
circumstances speculations as to its home seem futile. 

Though found in coast regions in all tropical latitudes, on both 
sides of the American and African continents, in Indo-Malaya, in 
Australia, and Polynesia, it seems to be less frequent in the New 
World ; but this is a matter that requires further investigation. It is 



MISCELLANEOUS PLANTS 



217 



distributed over the West Indian region, extending into subtropical 
latitudes on the Atlantic coasts of both North and South America. 
It grows on both sides of Central America, exists in the Galapagos 
Islands, and was observed by both Baron von Eggers and myself on 
the seashore and on the banks of estuaries in Ecuador. It was not 
observed by me in the Turks Islands, and apparently forms no feature 
either of the Bahamian or of the Bermudian flora. The plants in 
the Bermudas are stated to have been raised from seed washed 
ashore by the currents about three-quarters of a century ago (Chall. 
Bot, II., 128a). 

In Ecuador and in the West Indies it presented to me the same 
variety of stations at or near the coast that it displayed in the Pacific 
islands. Wherever it grows, it is as much at home on the borders 
of mangrove swamps and on the banks of estuaries as it is among 
the trees lining the beach. 

It is impossible to deal here with most of the points raised by the 
consideration of Hibiscus tiliaceus in the New World, a subject to be 
discussed at some future time. But here I may say that both in the 
Pacific islands and in the West Indies, as well as in Ecuador, there 
always seemed to me to be something refractory about its behaviour 
under the test of experiment and observation. The frequent diffi- 
culty in obtaining sound seeds, the difficulty in procuring their 
germination after prolonged flotation in sea-water, the variety of 
station, the inability to discover whether natives ever really did 
aid in the spread of the tree, its capacity for vegetative reproduction, 
the uncertainty about the agency of birds in its dispersal — these and 
other considerations often blocked the way when I was on the eve 
of obtaining a clear issue on some point connected with its distribution. 

Ipomcea carnosa, R. Br. 

This is an exceedingly interesting beach plant which, according to 
some authorities, is found over the warm regions of the globe, whilst 
others would limit its distribution chiefly to the New World with 
a representation in the Mediterranean and in a few island groups like 
the Hawaiian Islands and the Azores. When its synonym is freed 
from confusion, it is highly probable that in its range it will be found 
to rival the well-known shore species, Ipomoea pes-caprae, with which 
it is not infrequently associated on tropical beaches, though very 
far behind it in its frequency. Following Urban and Millspaugh, 
etc., who have most recently dealt with the plant, the following are 
amongst its numerous synonyms : Batatas acetoscefolia (Choisy), 
B. littoralis (Choisy), Convolvulus acetoscefolius (Vahl), C. littoralis 
(L. Syst.), C. repens (Sw.), Ipomoea acetoso3folia (R. and S.), J. arenaria 
(R. and S.), and J. carnosa (R. Br.). It has been confused with Con- 
volvulus soldanella, which may explain how that species has been 
sometimes accredited to the tropics of the Old World. It has not 
always been separated from Ipomoea pes-capra?, since Seemann 
includes /. carnosa (R. Br.) amongst its synonyms. 

Even the more limited conception of its distribution suggests 
that a plant which could reach islands in the middle of the Atlantic 



218 PLANTS, SEEDS, AND CURRENTS 



and Pacific Oceans might do a great deal more. Though, as is 
observed below, it is tenacious of locality, there are evidently some 
deterrent influences which restrict its dispersal, influences, however, 
that are not concerned with unfitness for dispersal by currents, since 
my experiments show that in their ability to float unharmed for 
many months in the sea its seeds are not inferior to those of Ipomcea 
pes-caprce, one of the most typical beach plants of the tropics. 

Let us look at some of the features of its distribution. In North 
America, according to the data supplied by Harshberger, it grows 
on the shores of the Mississippi delta, on the Louisiana beaches in 
association with Ipomosa pes-caprce, and around the coast lagoons 
near La Paz in Lower California. In the West Indies, as we learn 
from Grisebach, Hart, Millspaugh, and others, it grows on the 
beaches of Jamaica, the Cayman Islands, Porto Rico, and Trinidad ; 
and it has long been known from the Guianas and Brazil. It is also 
a Mediterranean plant, and it has been found also in the Azores 
as well as in the Hawaiian Islands in the centre of the Pacific. 

Until recently it was only known from one locality in the Azores, 
namely, Porto Pym in Fayal, where it was observed by Watson in 
1842, by Brown in 1894, and by myself in 1913 and 1914. However, 
during my stay on Pico I found it thriving on a beach just south 
of Magdalena at the western end of the island. In Hillebrand's 
Flora of the Hawaiian Islands it is only recorded from Niihau, an 
island at the extreme north-west of the group, where it was collected 
by Remy half a century or more ago. 

Its behaviour in the Cayman Islands is characteristic. Mr. Savage 
English in his account of Grand Cayman (Kew Bulletin, No. 10, 1913) 
refers to a small colony which had established itself on the shore 
in one locality, presumably after the hurricane of 1903, adding that 
it was new to the islanders. However, Dr. Millspaugh, who visited 
the Cayman Islands in February 1899, found it on the beach at Spot 
Bay in Grand Cayman, as well as on Cayman Brae (Plant. TJtow., L, 
85). The plant is evidently tenacious of locality, since it still grows 
in the Azores in the same locality where it was first noticed more 
than seventy years ago. Unlike its companion beach plant, Ipomcea 
pes-caprce, its stem is mostly buried in the sand, only the leaved 
and flowering shoots usually showing, a feature described in detail 
by Dr. Millspaugh. When I visited Porto Pym on March 12, 1913, 
only a few young leaf-shoots were showing above the sand. A month 
later they were much more numerous. On July 21, 1914, it was 
flowering abundantly and in early fruit; whilst numbers of the 
previous year's seeds bared of their hairy covering lay on the sand. 
On August 12 many of the capsules had matured and were opening, 
displaying their hairy seeds. 

To test their buoyancy, a number of the hairy seeds of the same 
year and of the bared seeds of the previous year were put in sea- water 
a few weeks after collection. After three months 20 per cent, of 
the hairy seeds and all of the bared seeds remained afloat, and 
after seventeen months 10 per cent, of the hairy seeds and 90 per 
cent, of the bared seeds were still floating. The survivors germinated 
freely, and from them I raised plants. If the currents are responsible 



MISCELLANEOUS PLANTS 



219 



for the existence of this plant in the Azores, the seeds must have come 
in the Gulf Stream drift in the company of the other West Indian 
seeds thrown up on these islands. It is true that the Mediterranean 
shores would offer a much nearer source ; but the current connections 
do not allow us to appeal to that region. It is, however, possible, 
as implied by Dr. Millspaugh in the case of Cakile edentula, its com- 
panion on the beach of Porto Pym, that it may have been introduced 
with ballast. But the same suspicion would fall on the other beach 
plants of this little bay, Polygonum maritimum, Salsola kali, Euphorbia 
peplis, etc. That West Indian seeds are sometimes stranded there 
is indicated by my finding on the same beach a seed of Sapindus 
saponaria apparently in a sound condition. 

Ipomcea pes-capr^:, Sw. 

Since this wide-ranging tropical beach plant has been discussed 
in detail in my book on Plant Dispersal in the Pacific, I will restrict 
my remarks mainly to its occurrence in the West Indian region. 
The circumstance that it came under my notice in Jamaica, Turks 
Islands, St. Croix, Grenada, and Tobago, as well as at Colon, suffi- 
ciently illustrates its general distribution over this area. From the 
data supplied by Grisebach, Millspaugh, Harshberger, etc., it is 
apparent that all the larger islands and most of the smaller ones 
possess this species. Excluding the small sand-keys, a few hundred 
yards across, I would imagine that this plant has established itself 
on every small island where there are beaches. Numbers of beaches 
were visited by me on the north, south, and west coasts of Jamaica, 
and the species was noticed on nearly all of them. However, certain 
restricting influences seem in places to affect its distribution. Thus, 
Mr. Lansing found it on only four of the nineteen Florida sand-keys 
examined by him, which contrasts with the prevalence there of 
such beach plants as Cakile fusiformis, Euphorbia buxifolia, and 
Suriana maritima that occur on most or on nearly all of them. 

In the West Indies this plant did not present itself to me far away 
from the beach, as it did in the dry inland plains of Vanua Levu, 
in Fiji, where it attained a maximum height of 1300 feet above the 
sea. The other botanists, whose works are at my disposal, say nothing 
of its inland extension in this region. In the Turks Islands it usually 
grows over the sandy and rocky surfaces of the smaller cays, which 
are often only one or two hundred yards across and display sea- 
drift thrown up by the breakers in the centre. In Gibb Cay, however, 
which is of greater height, the plants had climbed the sandy slopes 
to an elevation of nearly fifty feet. On the larger cays they thrive 
on the dunes behind the beach; but although the conditions in the 
interior of the islands seem very favourable for their inland exten- 
sion, I possess no record of their occurrence far from the beach. 

As in other parts of the tropics, the seeds are often to be found in 
stranded beach-drift; and there can be no doubt that the currents 
are effective agents in dispersing the buoyant seeds over these 
seas, since a good proportion can float unharmed for six months and 
more. They came under my notice on the beaches of Jamaica, 



220 PLANTS, SEEDS, AND CURRENTS 



Tobago, etc. ; and, as in the Turks Islands and elsewhere, seedlings 
that had raised themselves from stranded seeds were observed grow- 
ing in the beach-drift. 

I have been obliged to omit, on account of the limits of space, a 
very long note of many pages on the distribution of this plant in the 
warm latitudes of the globe as compared with Convolvulus soldanella, 
which takes its place on the beaches of temperate latitudes. As a 
rule, Ipomoea pes-caproz monopolises the coasts between the 30th 
parallels of north and south latitude, whilst Convolvulus soldanella 
holds the shores of the temperate zones beyond those latitudes in 
both the north and south hemispheres, though in the New World 
wide gaps may separate the two species. As far as I know at present, 
the ranges of the two species only overlap in Australia. It has long 
been known from the observations of Cheeseman that the two plants 
meet in the neighbouring Kermadec Group (lat. 31° 30' S.), and it 
would, therefore, be expected that the two plants would overlap on 
the eastern coasts of Australia. Mr. Maiden very kindly looked up 
the matter in my interests, and the conclusion he formed was that 
44 the two species overlap in northern New South Wales and in 
southern Queensland for at least 300 miles." Looking at the data 
which he supplied me it would be fair to conclude that the over- 
lapping takes place between the 25th and the 32nd parallels, Ipomoea 
pes-caproe reaching south to 32° S. and Convolvulus soldanella extend- 
ing north to 25° S. New Zealand, a home of C. soldanella, is well 
outside the zone of /. pes-capro3 and does not possess it. Prof. Ewart 
also supplied me with some valuable information on this point. 

The comparison has opened up so many problems of distribution 
in different parts of the world that it would take more space than can 
be allotted in these pages to deal satisfactorily with the subject. 
When I have filled up the numerous lacuna? in my research, I hope 
to publish it in the form of a paper. A short discussion of the ques- 
tion is given in my previous work on Plant Dispersal in Note 49 of the 
Appendix. 

Ipomcea tuba, Don. 

According to the various authorities at my disposal this plant is 
confined to the warm latitudes of the New World, where it is widely 
distributed, as in South Florida, the Bahamas, the Greater and 
Lesser Antilles, reaching south to the Guianas and Brazil. Urban 
regards it as almost cosmopolitan in the warm regions of the globe 
(Symb. Antill., IV., 513) ; but he seems nearly alone in holding this 
view. Though not known from the Bermudas, it was found both 
by Moseley and Ridley on the small Fernando Noronha group lying 
about 200 miles off Cape St. Roque (Chall. Bot., III., 19 ; Journ. Linn. 
Soc. Bot., vol. 27). 

Particulars as to its station are often lacking; but it is evidently 
as a rule a maritime plant, and in the manuscript of the Bahamian 
flora lent to me by Dr. Millspaugh it is described as a denizen of 
sandy shores in that archipelago; but I do not gather that it ever 
intrudes on the beach after the fashion of Ipomoea pes-caprce. Thus 



MISCELLANEOUS PLANTS 



221 



in the Florida sand-keys it grows with other littoral plants away 
from the beach. In the Turks Islands it thrives on both rocky and 
sandy slopes behind the beach. Dr. Millspaugh, in his paper on the 
Florida sand-keys, refers to its " often high location on many rocky 
Antillean islands." In another paper (Plantce Utowance) he alludes 
to it as growing over low bushes on the shores of Cayman Brae. 

The same American botanist shows that this plant, which is 
referred to under the synonym of Calonyciion album (House), grew 
always towards the centre of the sandy interior of the low islets 
forming the Florida sand-keys, removed alike from the mangrove 
border on the lee side and the beach on the weather side. Of 
nineteen islets examined, it was only found on four. 

It was only observed by me on three of the ten islands of the 
Turks Group, but never on the largest islands. On Gibbs Cay it 
grew in quantity over the sandy slopes and summit at a height of 
thirty to sixty feet above the sea, but not on the beach. On Pear 
Cay, where there is but little beach, it occupied much of the rocky 
surface, twenty to thirty-five feet above the sea. On Eastern Cay 
it did not grow on the extensive low sandy flats bordering the sea, 
but on its stony slopes fifty to sixty feet above the sea-level. 

The seeds are well suited for dispersal by currents. Of ten placed 
in sea- water in the Turks Islands all were afloat after forty-five days, 
the kernels being sound and quite dry. In a later experiment in 
England on seeds that had been gathered for fifteen months, 90 per 
cent, remained afloat after ten weeks, and from their condition they 
would evidently have floated unharmed for a considerably longer 
period. 

Laguncularia racemosa, G. 

This West African mangrove tree, which finds its most character- 
istic station, with Avicennia nitida, on the landward side of the 
mangrove swamp, is generally distributed in the West Indies, and 
has accompanied the other two mangroves, Rhizophora mangle and 
Avicennia nitida, in their extension to the Bermudas. It grows on 
the Atlantic side of the American mainland from Florida by way of 
Mexico and Venezuela to Rio de Janeiro (Schimper, p. 66), and also 
on the Pacific side on the Panama, Ecuadorian and Lower Californian 
coasts (Harshberger). 

The tree is dealt with in my book on Plant Dispersal, and here I 
will chiefly endeavour to supplement those remarks. It will be 
unnecessary to name the localities in which I noticed it, since it came 
under my notice wherever I examined the mangrove formation, as 
in Jamaica, Turks Islands, St. Croix, Grenada, Tobago, Trinidad, 
Colon, and Panama. According to Millspaugh it grows on ten of the 
fourteen Florida sand-keys that support mangroves, and is evidently 
one of the first plants to stock the emerging islet. 

Laguncularia racemosa is as a rule merely semi- viviparous. Only 
in rare instances does one find the radicle protruding from the fruit 
on the tree. Generally the dark green embryo does not effect more 
on the plant than the rupture of the thin seed-coats, the protrusion 
of the hypocotyl taking place shortly after the fruit has dropped 



222 PLANTS, SEEDS, AND CURRENTS 



from the plant, either on the mud or in the water. The enormous 
number of seedlings, only three or four inches high, that are at 
times to be noticed under the trees affords evidence of this partial 
vivipary. They are sometimes crowded together in thousands so as 
to almost form a turf, and the waste must be tremendous. Should 
the buoyant fruits drop into the water, whether into a river or into 
the sea, they quickly proceed with the germinating process, and can 
be carried in this condition for a great distance. Germinating fruits 
of Laguncularia are frequent in the floating drift of the estuary of 
the Guayaquil River in Ecuador, and I noticed them in a healthy 
state twenty miles out at sea with the protruding hypocotyl be- 
tween 3 and 12 mm. in length. In another locality, about three 
miles off the coast of Ecuador, I estimated that 90 per cent, of the 
floating Laguncularia fruits were germinating. The stranded fruits 
of L. racemosa were frequently found by me on the beaches of 
Jamaica, Tobago, Trinidad, etc., and they were nearly all germinating. 

The capacity of proceeding with the germinating process in sea- 
water has been already implied, and fruits in this condition can be 
transported far by the currents, more especially since fish do not 
nibble at the protruding seedling. It is not likely that any floating 
fruits could remain for more than a week or two in the sea without 
showing the radicle; and it is quite possible that the germinating 
fruits would survive the passage of two and a half or three months 
in the Equatorial Current from the West Coast of Africa to the shores 
of Brazil. That the New World derived its species of Laguncularia 
from the West Coast of Africa before the emergence of the Panama 
Isthmus seems probable. 

The fruits can withstand drying when detached from the tree in 
the entire condition. Five green non-germinating fruits were placed 
in sea-water in Jamaica after being allowed to dry in the air for 
nearly two weeks. A fortnight afterwards three were germinating 
healthily afloat. 

Comparison op the Shape and Dimensions op the Fruits op Laguncularia 
racemosa op the West Indian Region and op the Panama Isthmus with 
those op the Laguncularia of the Estuary op the Guayaquil River and 
of the neighbouring coasts of Ecuador. 





Form, etc. 


Length 


Breadth 


Laguncularia racemosa 
of the West Indies, etc. 


Broadens out into 
shoulders near the top. 
Ribs and wings more promi- 
nent. 


17 mm. 


8 to 9 mm. 


Ijaguncularia of Ecua- 
dor. 


Becomes narrower near 
the top. Ribs and wings 
less prominent. 


18 to 19 mm. 


6 to 7 mm. 



In my book on Plant Dispersal (p. 498) reference is made to the 
circumstance that the Laguncularia tree of the Guayaquil estuary 
and of the neighbouring coast swamps of Ecuador has a fruit differ- 



MISCELLANEOUS PLANTS 



223 



ing somewhat in form from that of the Laguncularia (L. racemosa) 
found on both coasts of the Panama Isthmus, and, I may here add, 
in the West Indies generally. Whether the difference is specific is 
doubtful. The fruit of the Ecuadorian tree is more symmetrical, 
longer and narrower, and does not broaden out into two shoulders 
near the top as in the case of the typical L. racemosa. 

LlMNANTHEMUM HUMBOLDTIANUM, Gr. 

This aquatic plant is distributed over the warm regions of the 
American mainland and in the West Indies. As observed in Jamaica 
it was equally at home on the exposed muddy borders of ponds and 
in the water. The moist seeds are globose, hairless, smooth, and 
1-5 mm. in diameter. In the wet state about sixty-three seeds go to 
a grain ; but in the dry state at least double that number would be 
required to make up that weight. On account of their oily surface 
the seeds float on the surface of a pond by throwing off the water, 
but when completely submerged they sink. They would thus be 
able to float for a long time in dry weather, and this would aid their 
early germination; but the raindrops would soon sink them. The 
seeds of our English species behave in a similar way, but here the 
flotation is assisted by a marginal fringe of hairs. These seeds are 
oval, flat, 4 to 5 mm. long, and have an oily surface, which 
enables them to repel the water ; but they can be sunk by dropping 
water on them. I observed the germinating process in both the 
English and West Indian species. Germination usually takes place 
in the case of sunken seeds, since from one cause or another the 
floating seed would soon be sent to the bottom in a pond. After 
the process is well advanced the seedling floats up and continues its 
growth at the surface. 

The general subject of the distribution of the genus is discussed 
in my work on Plant Dispersal. I have been familiar with these 
plants in England, Fiji, and Jamaica, and have formed the conclusion 
that in the tropics aboriginal man has often unintentionally assisted 
in their dispersal. He cultivates many of his edible tubers (Colocasia, 
Alocasia, etc.) at the borders of ponds and ditches where Limnan- 
themums thrive. 

LUFFA ACUTANGULA, Roxb. 

This is an introduced Asiatic species to which I refer here merely 
in connection with the slight floating power of its seeds. The seeds, 
as tested in the well-dried condition in Jamaica, sink in a day or two. 
Seeds of another cultivated introduced species were experimented 
on in Fiji, and found to sink after a few days in sea- water. The 
interest of these results lies in the circumstance that the seed of 
Luffa insularum, A. Gray (a maritime form of L. cylindrica), which 
grows in the Pacific islands on the shore and in the plains behind, 
are able to float in sea- water unharmed for months, and are doubt- 
less often dispersed by currents. This subject is dealt with on p. 426 
of my book on Plant Dispersal. This bears on the question of the 
connection between seed-buoyancy and a littoral station. 



224 PLANTS, SEEDS, AND CURRENTS 



The Turk's-head Cactus (Melocactus communis) of Turks 

Islands 

This plant, which figures on the farthing stamps issued in recent 
years for this colony, has a fancied resemblance to a man wearing a 
fez, and has given its popular name to the islands. It is still abundant 
on Eastern Cay and Cotton Cay, and, though now infrequent, was 
originally common on Grand Turk. The Rev. J. H. Pusey, for 
many years a Baptist minister in these islands, says in his handbook 
(Jamaica, 1897) that " it lasts a great number of years without the 
support of any earth whatever." Small specimens brought by me 
to England proved their capacity of surviving several weeks in a 
packing-case. At present there is a risk of this interesting plant 
being exterminated. I met a planter from the Caicos Islands in 
1911 who was taking several cases of them to the United States to 
test the market for their sale. This cactus is usually designated in 
general literature as Melocactus communis, DC, a species found 
also in Jamaica, Haiti, Antigua, etc. But in Britton's and Mill- 
spaugh's manuscript of the Bahamian flora it was regarded under 
the name of Cactus bahamensis as a plant restricted to the southern 
Bahamas (the Inaguas, Turks Islands, Caicos Islands, etc.). 

The small red juicy fruits, about 16 mm. long, contain minute 
black seeds rather over a millimetre in length, and well suited for 
dispersal by frugivorous birds. Another smaller cactus of similar 
habit of growth, which I take to be Mamillaria simplex, is associated 
with it on Grand Turk. It possesses seeds of the same size. The 
seeds of the common Opuntia tuna measure 5 mm. across. 



CHAPTER X 



miscellaneous plants (continued) 

MORINDA ROYOC, L. 

According to the data supplied by Grisebach, Hemsley, and 
Millspaugh this plant has a wide distribution in the warm regions of 
the New World, principally at or near the coast, or, as Hemsley 
puts it, " usually growing in maritime districts " (Chall. Bot., II., 38). 
The following are the insular and continental localities given : Ber- 
mudas, Florida, Bahamas, Cuba, Isle of Pines, Cayman Islands, 
Jamaica, Haiti, Honduras, and Panama. 

I was only familiar with it in Jamaica, where it was noticed in 
different localities near the beach on the north coast. Grisebach 
states that it was found by all collectors along the sea-coast of that 
island. But here it may also grow inland. Thus it was observed 
by me at the roadside a mile or two at the back of St. Anne's, and 
600 or 700 feet above the sea. In South Florida, according to 
Harshberger, it is an inland plant of the " banana holes " and of the 
"hammocks" (Trans. Wagner Inst., Oct. 1914). Millspaugh says 
that it occupies scrublands and pine-barrens in the Bahamas (Prcenunc. 
Baham.), and doubtless it often grows a considerable distance from 
the coast. According to the same botanist, it is known as " rhubarb ' ' 
in the Caymans and in the Bahamas. In the first-named islands it 
is employed medicinally in the place of that drug, and it furnishes a 
yellow dye. In its use as a dye plant it resembles Morinda citrifolia 
in the Old World, which has long served this purpose in the East. 

Its usual maritime station also links it with Morinda citrifolia, 
but there are other important similarities from the standpoint of 
dispersal. The Asiatic plant and the genus as a whole are dealt 
with from this point of view in my work on Plant Dispersal. It is 
there remarked that though the fruit of M. citrifolia soon decays 
when afloat, the woody, hard pyrenes possess great buoyancy, which 
they owe to a large bladder-like cavity, probably, according to 
Schimper, a modified seed-chamber. Though the pyrenes of M. 
royoc are smaller, they have the same characters and behave in the 
same way, their great floating capacity being connected with pre- 
cisely the same structure. Some of them which I placed in sea- 
water were all afloat and sound after five weeks, and gave promise 
of floating unharmed for many months. It is probably to this 
floating capacity of the pyrenes that the species owes its station at 
the sea-coast; and in this respect it is to be placed in the same 
q 225 



226 PLANTS, SEEDS, AND CURRENTS 



category as M. citrifolia, the pyrenes of which are often dispersed by 
currents. 

It is shown in my previous work that the fleshy fruits of this 
genus must often attract birds, and that the pyrenes could be readily 
transported by frugivorous birds across tracts of ocean. Nearly all 
of the fifty known species are inland plants ; and the indications are 
that only the littoral plants possess buoyant pyrenes, the bladder- 
like cavity being either absent or but slightly developed in the 
pyrenes of inland species. From its range over the warm regions of 
the globe Morinda is a very interesting genus for the student of 
distribution. Very noteworthy is it that quite 60 per cent, of the 
species are confined to islands, large and small, in Malaya and in the 
Indian and Pacific Oceans. 

Though this is predominantly an Old World genus, not more than 
15 per cent, of the species being restricted to America, the peculiar 
New World species have originated in several localities, as in Mexico, 
Guatemala, Yuca tan, Panama, Venezuela, Haiti, and Cuba. Nearly 
all these localities are given in the Index Kewensis. Urban has 
described a new species from Haiti under the name of M. buchii 
(Symb. AntilL, I., 481) ; and Dr. Greenman has in recent years dis- 
tinguished a new species, M. yucatanensis, which had been previously 
referred to M. royoc. It is found in brushlands and forests in the 
interior of Yucatan (Publication 126, Botanical Series of the Field 
Columbian Museum, Chicago, 1907). Nothing, however, is said of 
the distinctive structure of the pyrenes. The plant is known in 
Yucatan under the Mayan name of " Joyoc " (Hoyoc). If, as seems 
probable, this is a plant of the Royoc series, then we might here be 
presented with the case of a derivation of an inland species from a 
littoral species, a subject generally discussed in my book on Plant 
Dispersal. 

As regards the history of the American representatives of Morinda, 
I venture to hold, in spite of the numerical superiority of the genus 
in the Old World, that, like many other genera common to the 
western and eastern hemispheres, it originally spread from a common 
centre in high northern latitudes during one of the warm geological 
periods in those regions. 

Omphalea triandra, L. 

This tree, the " cobnut " of Jamaica, is interesting from the stand- 
point of dispersal by currents, since its seeds float buoyantly and 
occur occasionally in the drift on Jamaican beaches. The tree 
grows in hills behind St. Anne's in that island, and it was in this 
neighbourhood that I found the seeds on the beaches. The seeds 
are globose, about an inch in size, brown-coloured, and not unlike 
chestnuts in look. The buoyancy arises from a large internal cavity 
and also from the independent floating power of the kernel, portions 
of the albumen floating in water. The brown covering is seemingly 
waterproof, and no doubt the seeds would float for some time. It 
is, however, very doubtful whether they could find their way to a 
suitable inland station when stranded on a coast. Since the seeds 



MISCELLANEOUS PLANTS 



227 



of Omphalea diandra owe their floating power to the same causes, 
it is probable that this type of buoyancy is characteristic of the 
genus (see p. 159). According to Grisebach and Pax (Pflanzenreich, 
IV., 147, V.), Omphalea triandra has been found in Jamaica, Haiti, 
and the Guianas. 

Sc^vola Plumieri (Vahl) and Sc. Kcenigii (Vahl) 

One of the most characteristic of the littoral plants of the West 
Indies is Sccevola Plumieri. It is especially interesting from the 
standpoint of distribution, since, as in the case of other genera 
represented by littoral plants in this region, such as Rhizophora 
(p. 141), Tournefortia (p. 247), and Carapa (p. 141), it divides with a 
sister species the tropical shores of the world. In this case, however, 
there has been unfortunately some confusion between the two 
species, Sccevola Plumieri of the beaches of tropical America and 
tropical Africa, and Sc. Kcenigii of the beaches of tropical Asia, Aus- 
tralia, and Polynesia, a subject discussed in Note 5 of the Appendix. 
But the matter has been cleared up by Krause in his recent mono- 
graph on the Gocdeniacece (Das Pflanzenreich, IV., 277; 1912). The 
confusion in the synonymy quite obscured the issues raised in the 
matter of their areas of distribution. Now, as far as littoral plants 
are concerned, Sccevola comes into line with the other three genera 
above referred to. It puts much the same questions and raises 
much the same issues ; yet the differences that occur are in themselves 
full of suggestion for the future investigator. 

These two species, as I have said, occupy between them the 
beaches of the warm regions of the globe, both insular and conti- 
nental. As limited by Krause on pp. 18, 120, 121 of his memoir, 
Sccevola Plumieri occupies the shores of the West Indian islands 
and the eastern coasts of the American mainland from Florida by 
way of the Bay of Honduras to the shores of Brazil, reaching as far 
south as Rio de Janeiro. It extends northward to Bermuda. He 
does not give any station on the Pacific coast of America; but 
Grisebach and Hemsley record it from the Galapagos Islands (Flora 
Brit. West Ind.; Chall. Bot., IV., 161); and according to Baron von 
Eggers it is one of the " West Indian strand plants " that make up 
the " sand-flora " of the coasts of Ecuador (Deutsche Geogr. Blatter, 
heft 4, band 17, Bremen, 1894). Harshberger also gives La Paz 
(lat. 24° N.) on the coast of Lower California as a habitat (Phytogr. 
Surv. N. America, p. 639). Krause does not give many localities 
for the West Indian side of Central America; but the Caribbean 
shores of Mexico may here be mentioned as indicated by Britton 
and Millspaugh in the manuscript of their Flora of the Bahamas, 
and the last named specialty records it for the shores of Yucatan, 
near Progreso (Plantce Utowance, pt. L). It is also implied by 
Grisebach as existing on the Caribbean coasts. 

According to Krause, Sccevola Plumieri ranges along the West 
African coast from Senegal to Benguela, or through nearly thirty 
degrees of latitude (16° N. lat. to 13° S. lat), and along the whole 
coast of East Africa from Somaliland to the Cape. Further east- 



228 PLANTS, SEEDS, AND CURRENTS 



ward it intrudes into the area of Sccevola Kcenigii, attaining its limits 
in this direction in Southern India, Ceylon, and Mauritius; and at 
times both species are recorded from the same limited area, as in 
Mauritius. 

Generally speaking, the domain of Sccevola Kcenigii begins where 
that of Sc. Plumieri ends. It is not recorded either from the Pacific 
side of America, or from the East Coast of Africa, which in a general 
sense represent the limits of the area appropriated by its sister species. 
But between those continental coasts it ranges through the tropical 
zone, and sometimes extends beyond. Thus we find it on the 
beaches of the Pacific islands from Rarotonga to Hawaii and from 
New Caledonia to Liu-Kiu, in the northern part of Australia, in 
New Guinea and throughout Malaya, in South-eastern Asia, and in 
the islands of the Indian Ocean. It finally reaches its westward 
limits on the Malabar coast, in the Seychelles, and in Madagascar, 
but apparently not reaching the East Coast of Africa. 

It has already been said that these two interesting species of 
Sccevola, in dividing the coasts of the warm regions of the globe 
between them, raise the same issues as those presented by Carapa, 
Rhizophora, and Tournefortia, where in each case two sister species 
similarly divide the world; but there are important differences. 
Although one of the two littoral plants of each genus is widely 
spread in the New World, it is confined there in the case of Tourne- 
fortia. With Carapa and Rhizophora the American shore plant 
extends to the African West Coast, but is not found on the east side 
of that continent; whilst the American Rhizophora meets the 
Asiatic species in the Pacific islands, as in Fiji. 

Before going further something may be said of the genus to which 
the two littoral species of Sccevola, which are here compared, belong. 
Of eighty- three species recognised by Krause, fifty-eight, or 70 per 
cent., are confined to the Australian region. The rest are nearly 
equally divided between the Malayan region (including New Guinea) 
and the Pacific islands, excepting the two shore species with which 
we are specially concerned. 

Looking at the facts of distribution relating to the Goodeniaceae 
given in this monograph, one becomes conscious, as regards Sccevola, 
that one is dealing with a modification of a geographical type rather 
than with a genus as usually understood, since it is pointed out by 
Krause (p. 14) that of the thirteen genera in the family ten are confined 
to Australia and Tasmania, and that of the total of 291 species only 
twenty- seven, or 9 per cent., are found outside this region, the bulk 
of the species being restricted to the western half of Australia. It 
is of importance to note that of these twenty-seven species all but 
two species belong to Sc&vola, a very significant indication that 
this genus has been especially favoured in its means of dispersal. 

Sccevola, therefore, is not only in the main an Australian genus, but 
it belongs to a family that is also chiefly Australian. It is a member 
of a family that thrives where the physical conditions often deter- 
mine the xerophilous habit in plants, and, as I have before observed, 
this habit is the first requisite for a littoral station. It is, therefore, 
in this connection of special interest to refer to the remark of Krause 



MISCELLANEOUS PLANTS 



229 



(p. 19) that Sccevola as a genus has a characteristic inclination for a 
littoral life (" neigung fur das Litoralleben "). This inclination is 
well illustrated in the circumstance that many of the Australian 
species are equally at home in arid inland districts and at the coast, 
though very few are exclusively littoral in their station. The 
adoption of a station at the coast does not necessarily involve a 
wide range for a plant, the acquirement of buoyant qualities by the 
fruit or by the seed being as a rule needed for a wide distribution. 
In other words, the littoral plant must be suited for dispersal by 
currents to ensure a wide range. Thus it may be safely assumed 
that the five other species of Sccevola named by Krause (p. 19) as 
the most typical strand plants have but slight capacity for dis- 
tribution by currents, since they are all confined to Australia, and 
four of them are only known from West Australia. The origin of 
buoyancy in seeds is dealt with in detail in my book on Plant 
Dispersal. Buoyancy whether of seed or fruit is quite accidental as 
far as adaptation to dispersal is concerned. It is just as likely to 
be developed in inland plants, especially where dry conditions pre- 
vail ; and it is shown that in such cases, where the plants are xero- 
phytes, they tend to gather at the coast. But it is only the littoral 
station that determines its utility for dispersal, since it brings the 
plant with buoyant seeds or fruits within the influence of the currents. 

In many strand floras there is an element composed of local 
inland xerophilous plants, which, being at home in the neighbouring 
dry districts of the interior, encroach" in places on the beach, but 
through lack of fitness for dispersal by currents do not accompany 
the other beach plants with buoyant seeds or fruits that extend 
their ranges across the sea far beyond that particular locality. With 
the exception of Sccevola Kcenigii, it is probable that nearly all the 
Australian species of the genus that find their homes more or less 
frequently on the beach belong to this category. The littoral flora 
is liable to receive numerous accessions from the inland flora, where 
the conditions of the interior favour the growth of xerophilous 
plants. This I found to be especially the case in the Turks Islands, 
where the plants growing away from the beaches are mostly xero- 
phytes. So also on the Chilian beaches I found that the strand flora 
contained numerous intruders from the neighbouring dry inland 
regions (Plant Dispersal, p. 478). Schimper lays stress on the 
inclusion in the Indo-Malayan strand flora (p. 197) of colonists from 
sandy or stony places inland. Harshberger tells us how the numerous 
xerophytes of the chaparral scrub of the arid interior of Mexico and 
Texas descend to the plains that border the sea and extend along the 
shores of the Gulf of Mexico (p. 660, etc.). . 

I have here gone far enough to indicate the nature of the problems 
opened up when we recognise in Scwvola a genus eminently suited 
for supplying strand species. We are now in a better position to 
understand how the genus has come to furnish two of the limited 
number of strand plants that are cosmopolitan, or semi-cosmopolitan, 
in the warm regions of the globe, a considerable proportion when 
we reflect that even including the plants of the mangrove formation 
the total number would probably not exceed fifty. 



230 PLANTS, SEEDS, AND CURRENTS 



Before dealing with the means of dispersal of the wide-ranging 
littoral species, Sccevola Plumieri and Sc. Kcenigii, reference may be 
made to the genus in this connection. When in the Pacific the 
writer formed the opinion that the inland species, though not fitted 
for dispersal by currents, were well suited on account of their fleshy 
drupes for dispersal by birds, his observations and experiments 
indicating that only a littoral station was associated, as in the case 
of Sc. Kcenigii, with the capacity for distribution by currents (Plant 
Dispersal, p. 135, etc.). In this way, it was held, the range of such 
a shore species was enormously extended as compared with the 
inland species, nearly all of which were restricted to a particular 
group of islands or were confined to small areas. 

Krause (p. 14) deals with the subject; but his inferences were 
based entirely on the structural characters of the fruits. He con- 
siders that the fruits of Sccevola are adapted for two methods of 
dispersal — one by birds and other animals when the fruit has a fleshy 
covering and a hard endocarp, the other by currents where the 
endocarp has a cork-like outer layer suggestive of buoyancy in the 
fruit. In illustration of dispersal by currents he takes four West 
Australian species of dune plants growing on and near the coast, as 
well as Sccevola Kcenigii, the widely ranging strand plant of the Old 
World ; but no results of experiments are given and none are referred 
to, since they did not come within the scope of the work. Amongst 
examples of dispersal by birds he mentions the strand plant of the 
New World and of both the African coasts, Sccevola Plumieri, for 
the fruits of which only dispersal by birds seemed possible, the 
agency of the currents being excluded. I formed the same opinion 
on first examining these fruits in the West Indies, but experiments 
showed that they are also well fitted for distribution by the currents. 

The two modes of dispersal of the fruits of Sccevola have long been 
established by Schimper, myself, and other students of distribution. 
They may be combined in the same species, as with the two world- 
ranging beach plants Sc. Kcenigii and Sc. Plumieri, the juicy exocarp 
attracting the bird, and the buoyant stone fitting the fruit for trans- 
port by the currents. Schimper first apportioned their true values 
to these two capacities in the same species when in the case of Sc. 
Kcenigii, in his book on the Indo-Malayan strand flora (p. 156), he 
regarded the fruits as fitted for dispersal over long distances by the 
currents and for short distances by birds. The fruit is specially 
described and figured in his work (p. 172). 

Yet it is evident from the treatment of Sccevola by Krause in this 
monograph that the greater number of the species have dry or hard 
fruits that would not be especially attractive for birds. In this 
connection it is very significant that the two sections, Sarcocarpcea 
and Xerocarpcea, which derive their names respectively from the 
fleshy and from the dry character of the fruits, include in the case 
of the first named the species that are established in localities farthest 
away from the Australian home of the genus, and in the case of the 
second named nearly all the species of the genus that are confined 
to Australia. The section Sarcocarpoea includes not only the inland 
species that have established themselves through the agency of 



MISCELLANEOUS PLANTS 



231 



birds in distant islands of the tropical Pacific, as in Hawaii and Fiji, 
but the two world-ranging shore plants, Sccevola Kcenigii and Sc. 
Plumieri, which owe their wide dispersion mainly to the currents, 
but also to some extent to birds. The great increase in the range 
due to the capacity for dispersal by currents is well illustrated by 
these two strand species of Sccevola, there being but little probability 
that other species of the genus possess fruits capable of floating 
unharmed for long periods in the sea. 

It is not likely that the buoyancy which Krause assumes on 
structural grounds for the fruits of four littoral Australian species 
of Sccevola can be very marked, since none of them are known from 
outside regions and three are confined to West Australia. Yet the 
principle involved may be correct, and we may have here reproduced 
the behaviour of Terminalia, as described by Schimper in his book 
on the Indo-Malayan strand flora (p. 180). In this genus, although 
the fruits of several inland species possessed floating powers asso- 
ciated with buoyant tissue in their coverings, the fruits with by far 
the greatest floating capacity and with the greatest development of 
buoyant tissue were those of Terminalia katappa, the only character- 
istic shore species and the one most widely spread. 

I will now deal more especially with the American and African 
shore plant, Sccevola Plumieri, contrasting it as regards its modes of 
dispersal with the Asiatic and Pacific littoral species, Sc. Kcenigii. 
Having been for many years familiar with the Asiatic species, in 
Java, Polynesia and the Keeling Islands, I have been at length able 
to compare its behaviour with its sister species of the Atlantic 
region. This was accomplished in the Turks Islands at the south- 
east end of the Bahamas, where I enjoyed abundant opportunities of 
studying the plant. 

As regards its distribution in the West Indian region the data 
show that Sccevola Plumieri is spread over the Bahamas and the 
Greater and Lesser Antilles; but apparently it is absent from 
Trinidad. It extends north to South Florida and reaches Bermuda. 
In the Florida sand-keys it does not seem to be at all frequent, since 
Mr. Lansing found it on only four of the nineteen keys examined, 
and in only one of them did it exist in any quantity. The shrub, it 
may be added, is much less hardy than that of Sc. Kcenigii, and it 
evidently has greater difficulty in establishing itself on a fresh coast. 
It is noteworthy in this respect that in March 1895 Dr. Millspaugh 
found only a single individual on the Alacran Shoals (Plantce 
Utowance). 

In the Turks Islands, where it attains usually a height of from two 
to two and a half feet, it is known as the Ink-berry plant, on account 
of its black, juicy fruits of the size of a large cherry. Its distribution 
in this small group is irregular and varies from year to year, a result 
due to the destructive action of hurricanes in the smaller keys or 
cays, and to its being much appreciated by cattle and goats in the 
larger islands, the whole plant being often devoured. I was informed 
by a resident that it thrives only on beaches to which animals cannot 
get access. Compared with the more woody plants of the beaches, 
such as Tournefortia gnaphalodes and Suriana maritirna, these more 



232 PLANTS, SEEDS, AND CURRENTS 



or less fleshy shrubs cannot withstand the hurricanes and gales. 
They are not able, as in the cases of the two plants just named, to 
maintain their position by at first growing prone and sending down 
secondary rootlets into the sand. On the southernmost and most 
exposed island of the group, Greater Sand Cay, an island that is 
wind-swept to a degree not easily realised without a sojourn in these 
tempestuous seas, and one that is often breached by the breakers 
in several places during storms, this plant was scarcely represented 
when I visited it in March 1911. A few young plants grew on the 
weather side, and there were some seedlings growing amongst the 
stranded drift. The presence of a few goats on the island may 
partly explain this ; but, as shown below, the much hardier bushes 
of Suriana maritima have suffered severely in recent storms, and 
much of the vegetation growing on the beaches was swept away 
under the combined influence of wave and wind during the last 
hurricane. 

On Grand Turk, the largest island of the group, the plant was 
common in places on both coasts. It was thriving on Gibbs Cay, 
ascending the sandy slopes some twenty or thirty feet; but I did 
not observe it on Round Cay. On the rocky islands of Long Cay, 
Pear Cay, and Penniston Cay, where beaches are absent or scanty, it 
did not come under my notice at all ; and the same may be said for 
Eastern Cay. On Cotton Cay I did not see it; but only a portion 
of its coast was examined. On Salt Cay it did not often present 
itself; but I found it flourishing near its southern extremity. On 
Greater Sand Cay, as already observed, it barely existed. This 
completes the list of the islands of this small group. 

We come now to discuss the dispersal of this plant by birds and 
by currents, and in these respects we will compare it with Sccevola 
Kcenigii. There is no doubt that the fruits of both plants can be 
distributed by birds as well as by the currents ; but, as has already 
been pointed out, whilst the bird would be an effective agent in 
local dispersal, as from island to island within the same group, it 
is to the current that we must look for the agency concerned in 
distribution over the breadth of an ocean. The importance of the 
bird in the case of Sccevola Plumieri is emphasised by Dr. Millspaugh 
in his paper on the Florida keys, where he remarks that " the black, 
pulpy fruits of this plant form a very attractive food for land birds ; 
it thus becomes scattered far throughout the Antillean region " 
(p. 240). This is also the opinion of Krause, who would exclude the 
possibility of current agency altogether (p. 14). However, neither 
Millspaugh nor Krause refer to the results of any flotation experi- 
ments, and the former was surprised when I showed him in the Turks 
Islands a cup of sea- water in which the " stones " of Sccevola Plumieri 
had been floating for several weeks. The bird for local distribution 
and the current for oceanic transport : this was the conclusion 
formed concerning Sccevola Kcenigii by Schimper and myself. It 
applies also, as my West Indian results indicate, to Sccevola Plumieri. 

In both cases the fruits, or rather their " stones," are able to 
float in sea- water for months, and in that of Sco3vola Kcenigii for a 
year or more, the seeds remaining fresh and, when tested, retaining 



MISCELLANEOUS PLANTS 



233 



their germinative capacity. Yet, strange to say, the fruits of these 
sister species, so similar in station and in habit, exhibit very different 
types of buoyancy. In both cases the maintenance of the floating 
powers depends on the " stone " ; but there the similarity ends. In 
both plants the fresh drupe floats in sea-water, and the buoyant 
stone is freed in a few days by the decay of the fruit. This, however, 
is not the usual course of events in nature, since the fallen drupe 
generally loses its soft parts whilst lying on the sand beneath the 
bush, and it is the more or less dry stone that is swept into the sea. 
The stones form a regular constituent of the smaller beach-drift in 
the different parts of the tropics where the two plants grow. 

I will first take the West Indian species, Sc. Plumieri. Should 
the fresh black drupes get into the sea, experiment shows that they 
will sink in two days, the buoyant stone, on being freed from the 
decaying fruit, soon floating to the top. But, as just remarked, it 
is the more or less bared stone that is usually picked up by the wave 
from the beach. These stones, ovoid in form, prominently tubercled 
on the surface, and 9 or 10 mm. in length, do not possess buoyant 
tissue of any sort, neither the hard material of the stone nor the seed 
within possessing any floating power. The outer cork-like covering, 
which, as described below, endows the stones of Sc. Kcenigii with 
buoyancy, is not here represented. The floating capacity of the 
stone of Sc. Plumieri is due to the circumstance that only one of its 
two cells holds a seed. The empty cell, which is water-tight and 
usually contains the seed envelopes, gives floating power to the 
stone. This can be proved in different ways. The most striking 
proof is this. If we take a buoyant stone and remove the portion 
containing the empty seed-cavity, it sinks at once. But if we 
remove the portion holding the seed, it floats still more buoyantly, 
almost like a piece of cork. It does not follow that the two-celled 
stones of this plant never have both cells filled with a seed. My 
observations, however, indicate that stones with one cell empty 
predominate. In fact, two- seeded stones very rarely came under 
my notice. 

Though it is usually the bared stone of Sccevola Kcenigii that is 
picked up by the waves as it lies on the beach, the fresh drupe may 
at times be carried off by the sea. In that case it floats buoyantly, 
and when after a few days' immersion it loses its white, fleshy cover- 
ing, the stone remains at the surface. As studied in the homes of 
the plant by Schimper (p. 172) and myself, the cause of the buoyancy 
lies in a layer of cork-like, air-bearing tissue investing the stone 
proper. If this covering is removed the stone sinks, neither the 
hard material composing it nor the seeds possessing any floating 
power ; and I may add that the two cells of the stone in each case 
hold a seed, so that the question of buoyancy of the type presented 
in the instance of Sc. Plumieri is not raised. It may be remarked 
that the stone proper of Sc. Kcenigii is much smaller than that of 
the West Indian species, being rounded, about 5 mm. across, and 
slightly tubercled. 

The stones of the drupes of these two species of Sccevola represent 
two quite different types of buoyant fruits, types that are describe d 



234 PLANTS, SEEDS, AND CURRENTS 



in Chapter XII. of my book on Plant Dispersal. Those of Sc. Koenigii, 
which are described and figured by Schimper in his work on the 
Indo-Malayan strand flora (p. 172, pi. vii.), belong to a type that 
includes many of the characteristic littoral plants of the Indian and 
Pacific Oceans, the buoyant tissue forming part of the fruit- coverings. 
Since the question of adaptation was raised by Schimper in their 
case I termed them the " adaptive " group, though not myself in 
agreement with him on that point. 

However, the interesting thing is that the type of buoyancy 
represented by the stones of Sc. Plumieri is offered by plants where 
this question of adaptation could not be raised. It corresponds 
with the Premna type, which is discussed at length on pp. 112 and 
561 of my book above quoted. The behaviour of the small drupes 
of a littoral species of the genus is exactly that of the West Indian 
Scoevola Plumieri. The Premna drupes floated at first, but the 
buoyant stones are soon freed by the decay of the soft parts. Neither 
the seeds nor the substance of the stone are buoyant, the stone 
deriving its floating power from the fact that three of its four cells 
are usually empty. The importance of the bearing on the question 
of adaptation to dispersal by currents of the contrast presented by 
the two shore species of Sccevola is obvious. If the buoyant quality 
is accidental in its origin in one species, it is not reasonable to assume 
that it is adaptive in the other. 

The results of my experiments on the floating powers of the stones 
of the drupes of these two species of Scaevola now require a few 
remarks. As long ago as 1888 I tested the buoyancy of those of 
Sc. Koenigii on Keeling Atoll, the results being given in my paper on 
the plants of that locality which was published in the journal of the 
Victoria Institute of London in 1889. Ripe fruits gathered from 
the plant continued to float buoyantly after fifty days' immersion in 
sea- water, losing during the early days of their flotation their white 
fleshy covering. Subsequently three of the stones were sown out by 
Dr. Treub at Buitenzorg, and out of the six seeds that they contained 
five germinated in the course of the next two months. Twenty-one 
months afterwards I put in sea- water in England two fruits gathered 
on Keeling Atoll. Both floated after a year's immersion, the seeds 
proving to be quite sound (see Plant Dispersal, p. 531, and Note to 
the Keeling Atoll paper). 

My first experiments on the fruits of Sccevola Plumieri were carried 
out in the Turks Islands in 1911, the average result being that about 
70 per cent, remained afloat after sixty-three days in sea-water. 
The stones that had lost their soft coverings whilst lying under the 
bushes on the beach sand were the most buoyant. About 60 per 
cent, of the fresh stones and about 80 per cent, of the old dry stones 
floated after six weeks. In all cases the seeds of the floating stones 
proved to be sound and healthy at the close of the experiments. 
It was ascertained that the sinking was due to water penetrating the 
empty cell, the cell containing the seed being usually quite dry. 
In later experiments made in England on stones that had been 
collected ten months and still possessed sound moist seeds, I found 
that 66 or 67 per cent, floated after eighteen weeks in sea-water. 



MISCELLANEOUS PLANTS 



235 



But only half of the survivors proved to have been quite impervious 
to water. In the other half, water had begun to penetrate into the 
empty cavity as well as into the cavity containing the seed ; and as 
they all sank in fresh-water the limits of their floating powers had 
evidently been nearly reached. The upshot of the experiments was 
that only a third of the stones were in a sound germinable condition 
after eighteen weeks' flotation in sea- water ; and I would imagine that 
a period of five to six months would represent their flotation capacity. 

On the whole the results of experiments on the capacity for dis- 
persal by currents possessed by Sccevola Plumieri and Sc. Kcenigii 
go to show that although in both cases the stones will float unharmed 
for months in the sea, the advantage is certainly on the side of the 
plant last named. We would expect that floating capacity dependent 
on the existence of buoyant tissue in the fruit-coverings would be 
more effective than when determined by the failure of seeds and the 
resulting empty cavity. Whilst the stones of Sccevola Kcenigii will 
float in sea- water for a year or more, those of Sc. Plumieri will on the 
average float in a sound condition for only four or five months. 
Those of the first-named species could very well be drifted across an 
ocean as broad as the North Atlantic; but this would not be prac- 
ticable for those of Sc. Plumieri, their floating powers only allowing 
them to reach Bermuda from the Florida coasts, the transatlantic 
traverse, occupying twelve months and more, being impracticable. 
But although the transference of Sc. Plumieri from the New World 
to West Africa by the only available route in the Gulf Stream drift 
would be impossible, the passage from tropical West Africa to Brazil 
in the Main Equatorial Current would be quite within the floating 
capacity of its fruits, since, as shown in Chapter III., it could be 
performed in three months. I have not here referred to the possi- 
bility of a passage to West Africa in the Counter Equatorial Current, 
since there is little to indicate that it is an available route for seed 
dispersal. 

When, therefore, we discuss from the standpoint of dispersal by 
currents the question whether Sccevola Plumieri has reached the 
West Coast of Africa from America, or the Atlantic coasts of America 
from Africa, we have to exclude the long easterly passage in the 
Gulf Stream drift in preference for the westerly passage in the swift 
Main Equatorial Current from the Gulf of Guinea to the coasts of 
Brazil. From the standpoint of distribution a consideration of the 
same question leads to the same results. There is nO probability 
that the American region could have received this plant from across 
the Pacific. Although Australia is the home of the genus, Sc. 
Plumieri does not occur there, or, in fact, anywhere in that region 
of the globe. We have, therefore, to choose between America as 
the birthplace of the species or America as its recipient from the 
African West Coast. Although in the Index Kewensis America is 
credited with two endemic species of Sccevola, one in Trinidad and 
the other in Central America, these are both disregarded by Krause, 
who includes the species of the second locality (Sc. cumana) amongst 
his doubtful species (p. 168). No species of the genus is mentioned 
in Hart's list of the Trinidad flora. There is, therefore, little reason 



236 PLANTS, SEEDS, AND CURRENTS 



for supposing on the grounds of the distribution of the genus that 
America is the birthplace of this species. All the indications favour 
the view that it has received it from the shores of the nearest portion 
of Africa. 

In the case of Sccevola Plumieri another difficulty presents itself 
in connecting its ranges on the East and West Coasts of Africa. 
Though it reaches the Cape or its vicinity on the east side of the 
continent, there seems to be a gap of about twenty degrees of lati- 
tude on the west side between the Cape and Benguela, where, accord- 
ing to the data supplied by Krause, it is next found. Probably 
future records will bridge over this broad gap; and we can only 
suppose that the species originally found its way north along the 
African West Coast through the combined agencies of birds and of 
inshore northerly currents. That it reached this coast from the 
eastern side of the continent is very probable. This involves the 
doubling of the southern extremity of Africa ; but it has been shown 
in Chapter III. that this has been performed by bottle-drift. 



Tabulated Results of the Comparison of Scjevola Plvmiem, Vahl, 
and scmvola k(enigii, vahl. 





Scaevola Plumieri 


Scaevola Koenigii 


Distribution. 


Pacific coast of tropical 
America and the Galapagos 
Islands. 

East coasts of tropical 
America from Florida to Rio 
de Janeiro, including the West 
Indies and Bermuda. 

West Coast of tropical Africa 
from Senegal to Benguela. 

East Coast of tropical Africa 
from Somaliland southward 
and extending to the Cape. It 
reaches eastward to Southern 
India, Ceylon, and Mauritius. 


Islands of the Indian Ocean 
extending westward to the 
Malabar coast, the Seychelles 
and Madagascar, but not re- 
corded from the east coast of 
Africa. 

South-eastern Asia, extend- 
ing north to the Liu-Kiu 
Islands and eastward through 
Malaya to New Guinea and the 
northern coasts of Australia. 

Islands of the tropical Pacific 
as far east as the Low Archi- 
pelago and as far north as the 
Hawaiian Islands. 


Characters of 
fruit. 


Black juicy drupe. Stone 
ovoid, markedly tubercled, 9 
to 10 mm. long, no covering 
of buoyant tissue, two -celled, 
one cell empty. 


White fleshy drupe. Stone 
roundish, slightly tubercled, 
5 mm. across, possessing an 
outer covering of cork-like 
buoyant tissue, two -celled, 
both cells holding a seed. 


Buoyancy of 
fruits in sea-water. 


Stones float for four or five 
months with seeds sound. 


Stones float for twelve 
months and more with seeds 
sound. 


Cause of the 
floating capacity. 


Buoyancy of stone is en- 
tirely due to the empty cell. 


Floating power of stone is 
entirely due to the buoyant 
tissue investing it. 


Agents of dis- 
persal. 


Currents across tracts of 
ocean. 

Frugivorous birds for local 
dispersal. 


Currents across oceans. 
Frugivorous birds for local 
dispersal. 



MISCELLANEOUS PLANTS 



237 



SOPHOEA TOMENTOSA, L. 

This littoral shrub, which ranges over the warm parts of the globe, 
is discussed at length in my book on Plant Dispersal. My remarks 
here will be accordingly restricted to some supplementary observa- 
tions made in the West Indian region. Though widely distributed 
in the West Indies and extending to South Florida and Bermuda 
and along the Caribbean shores of Central America to Brazil, it does 
not appear to be of frequent occurrence. Whilst typically at home 
on a sandy beach, it may also grow on rocky shores, as occasionally 
happens in Jamaica and, according to Harshberger's work (p. 674), 
also in Cuba. 

The plant came under my notice more particularly on the north 
coast of Jamaica, in the Turks Islands, and on the Colon beaches. 
In the Turks Group it only came under observation in one island, 
namely, on Grand Turk; and there it was frequent in the interior 
of the low, sandy southern third of the island, where it grew in the 
company of Coccoloba uvifera, Dodoncea viscosa, and other plants, 
but was never observed amongst the vegetation immediately border- 
ing the beach. The beach conditions are, however, reproduced in 
the plains of the interior, where the plant thrives at distances never 
exceeding half a mile from the beach. It appears to have a difficulty 
in establishing itself on low, sandy islets in these seas on which many 
characteristic shore shrubs find a home. Thus, Mr. Lansing did not 
record it on the Florida sand-keys, of the vegetation of which he 
made a most methodical investigation. As illustrating its transient 
sojourn on small isolated island groups one may refer to a note on 
this subject by Mr. Savage English in the Kew Bulletin for 1913. 
He refers to a solitary specimen on the shore of Grand Cayman which 
was washed away in the hurricane of 1912. 

In the district of St. Anne's on the north side of Jamaica I had 
an opportunity of observing the influence of an inland station on the 
buoyancy and size of the seeds. The seeds of the strand plant, as 
is shown in my previous work, are able to float in sea-water un- 
harmed for several months, and even after twelve months' immersion. 
It is also established in its pages that with the seeds or fruits of 
typical beach plants like Ipomcea pes-caprce, Scazvola Koenigii, etc., 
the buoyant capacity is as a rule maintained when the plants have 
extended inland several miles from the coast. This conclusion is 
generally supported by the behaviour of Sophora tomentosa in 
Jamaica; but at the same time it was elicited that although the 
seeds of the inland plants floated in sea- water as long as those of the 
beach plants they did not do so in the same proportion, a greater 
number of them sinking during the experiment — a result, however, 
that is to be connected with the moister climatic conditions of the 
inland station. 

I found the plants well established at the roadside and on the hill- 
slopes just below " Sussex," which lies at the back of St. Anne's 
about two miles inland and about 700 feet above the sea. Their 
seeds were compared with those of shore plants growing at the 
St. Anne's coast on Priory Islet. The estate known as " Sussex " 



238 PLANTS, SEEDS, AND CURRENTS 



lies a little below the zone of heavy rainfall ; but the climatic con- 
ditions there are far more humid than on the coast beneath. This 
distinction is important, because it is bound up with different degrees 
of shrinkage of the coast and inland seeds, and with the consequent 
different degrees of impermeability. As indicated below, the coast 
seeds are smaller and lighter, contrasts which my observations on 
seed-impermeability enable me to connect with a greater degree of 
imperviousness resulting from more complete shrinkage of the seed- 
coats. The coast seeds were 5-5 to 6 mm. in size and averaged 
1-3 grains in weight; whilst the inland seeds measured 6-5 to 7 mm. 
and had an average weight of 2 grains. 

The difference in behaviour is at once shown in an experiment 
in sea-water commenced by me in Jamaica, continued there by 
Mrs. H. B. Warde after I had left for England, and concluded by 
me on my return to the island about half a year afterwards. Of the 
coast seeds, 95 per cent, were afloat after seven and a half months, 
and no more sank when the experiment was extended to nine months, 
the seeds being still hard and sound. Of the inland seeds some 
began to swell and sink after two months; but 60 per cent, were 
afloat, and hard and sound, after seven and a half months. Some 
of the sunken inland seeds germinated in the sea- water and plants 
were raised from them. In another sea-water experiment carried 
out by me in Jamaica the contrast in behaviour was greater. After 
a month all the coast seeds were afloat in their normal state; but 
several of the inland seeds began to swell in a few days, some of 
them germinating in the sea- water, and only 10 per cent, remained 
afloat in a hard, sound condition after a month. In a third sea- 
water experiment conducted in England in the same year, under 
warm conditions imitating those of the tropics, all the coast seeds 
were afloat and normal after four months, whilst 69 per cent, of the 
inland seeds alone floated ; the rest, having absorbed water, swelled 
and sank. All the seeds employed in these experiments were of the 
previous season's growth. It appeared in the course of this inquiry 
that the " scar " was the place of weakness in the inland seeds as 
regards the penetration of water. 

The seeds experimented upon were gathered from the well-dried 
pods hanging on the coast and inland trees at the end of March 1907. 
In both localities the previous year's pods were hanging in bunches 
from the trees. In neither locality were the trees then in flower; 
and whilst the coast plants were leafless, the inland trees displayed 
abundant foliage, a contrast connected with the prevalence of more 
humid conditions in the inland station. 

The bearing of these Jamaican experiments may be thus stated. 
My experiments in the Pacific on the influence of an inland station 
on the buoyancy of the seeds or fruits of typical shore plants were 
concerned with plants that had extended miles inland in dry districts 
where plants of the xerophilous habit prevailed. Here in Jamaica 
we had typical shore plants invading the fringe of the lower forest 
zone, where more humid conditions determined the hygrophilous 
habit. The results obtained in Fiji and those obtained in Jamaica 
are therefore in one sense not strictly comparable. In the first 



MISCELLANEOUS PLANTS 



239 



case, the xerophyte of the beach found conditions suited for xero- 
philous plants in the dry inland districts ; whilst the fruits matured 
and the seeds underwent the shrinking and hardening process under 
somewhat similar circumstances in both stations. In the second 
case, the xerophyte of the beach was placed under different climatic 
and soil conditions in the lower forest zone. The fruits matured 
and the seeds hardened in a moister climate, and we have seen 
how the whole plant responded, since the inland plants were in 
full leaf in the spring whilst those on the beach were leafless. 

The conclusion to be drawn from these experiments is, that whilst 
the buoyancy of the seeds of littoral plants is retained when the same 
plants grow inland, whether in moist or dry conditions, it is less 
persistent when the inland plants grow in the humid conditions of 
the lower woods than with those growing in plains or open- wooded 
districts where drier xerophytic conditions prevail. The buoyancy 
is retained, therefore, when the xerophytic conditions of the coast 
are preserved in inland plains. It tends to disappear under the 
moist conditions of the inland forests. We have here indicated 
how it comes about that in a genus holding both littoral and inland 
species the seeds or fruits of the former float and of the latter sink. 
This is illustrated in the case of Sophora in the Pacific islands, where 
the seeds of the wide-ranging shore species, S. tomentosa, float, and 
those of the inland species, as exemplified by S. chrysophylla of the 
Hawaiian forests, sink. 

It is probable that Sophora tetraptera, a tree of New Zealand and 
South Chile, which grows at the coast but also grows inland, would 
display buoyant seeds only when growing at or near the coast. 
In an experiment on the seeds of the tree that I collected on the Chilian 
coast it was found that half of the seeds floated in sea-water after 
seven months' immersion. Two of them placed in soil germinated 
and produced healthy plants. This is an extension of an experiment 
described on p. 580 of my work on Plant Dispersal. 

A word may here be said about the source of Sophora tomentosa in 
the New World. As far as the currents are concerned, it is far more 
likely that its floating seeds reached Brazil by the short route in 
the Main Equatorial Current from the Gulf of Guinea than that they 
were carried in the Gulf Stream drift from the West Indies to Africa. 
Yet the genus holding some thirty species is spread over the warmer 
regions of both hemispheres. North America has its own species 
that flourish in the prairie districts, in the North Mexican highlands, 
and in the Rocky Mountains (Harshberger's Phyt. Surv. N. America). 

SURIANA MARITIMA, L. 

This shrub, the sole species of the genus, is one of the most widely 
spread of tropical strand plants. It occurs in the Pacific islands, 
on the northern coasts of Australia, in Malaya, in the islands of the 
Indian Ocean, on the shores of the Asiatic mainland, on the East 
Coast of Africa, but not, as far as I know, on the West Coast of that 
continent, though its occurrence there is extremely probable. In 
the New World it is widely spread over the West Indies, occurring 



240 PLANTS, SEEDS, AND CURRENTS 



even on such isolated groups as the Cayman Islands and the Alacran 
Shoals (Millspaugh). It is also a Bermudian plant. On the American 
mainland it is found on the coasts of South Florida and on the shores 
of the Gulf of Mexico. I have no record of its occurrence on the 
Pacific coasts of that continent, but it ought to grow there. 

There are, however, some curious gaps in the distribution of a 
plant that Nature evidently intended to be universal on tropical 
shores. For instance, its distribution in the Pacific is freak-like. 
It has been recorded from Tonga, but not from Fiji or Samoa. Yet 
it occurs in the Melanesian archipelagoes of the Western Pacific. 
Though found in the Tahitian Group and in the Paumotu Islands, 
it has not been observed in Hawaii. We have here, it would seem, 
an outcast in the plant world, friendless, without kith or kin, and 
claimed by nobody, since botanists are undecided in what order to 
place it. It would be futile to seek for its home. It is probably 
coeval with man in the tropics, and he has evidently been its greatest 
foe. 

Its suitability for firewood no doubt explains its otherwise unac- 
countable absence from some of the Pacific archipelagoes. One 
of the first things a Pacific islander does, when he lands on an unin- 
habited shore, is to gather fuel for cooking his yams or his taro- 
roots ; and if, as often happens on coral islands, fishing parties make 
a sojourn there of some weeks, the wood of this shrub would be 
burned in quantities. This inimical influence would not be an affair 
of to-day but of the ages. It goes to explain why the plant was 
not recorded by botanists from Keeling Atoll before my visit in 1888 
(vide Keeling Atoll paper), since long before the white man's occupa- 
tion of the islands they had probably been visited from time to 
time by Bugis traders. 

Though typically a plant of the borders of the sandy beach and 
of the sand-dune, it may also grow on coastal rocks as in Bermuda 
and in the Bahamas (Harshberger). I came upon this shrub growing 
on the north coast of Jamaica at St. Anne's, and at Dry Harbour 
and on the south coast at Paroti Point. But it was in the Turks 
Islands at the south-east end of the Bahamas that I paid especial 
attention to it. However, before proceeding to refer to its occurrence 
in that small group I will notice its distribution in the sand-keys 
of Florida, as observed by Mr. Lansing and described by Dr. 
Millspaugh. Out of nineteen keys examined westward of Key West 
this plant was noted in all but two; but usually it was infrequent 
and represented by only one or two small colonies growing in its 
natural station on the sandy soil to the rear of the mangrove belt. 
Only in four keys was it at all frequent, and in two of these it occupied 
most of the surface of the islet. In the past, no doubt, man did much 
to disturb the distribution of this plant in the Florida keys by 
utilising it for firewood 

In the Turks Islands, though a characteristic strand plant, it as 
a rule presents itself in the rear-line of the beach vegetation when 
any arrangement can be detected. But it is equally at home on 
the sand-dunes behind the beach; and in the smaller cays, when 
sand has been spread over the island, it also occupies the interior 



MISCELLANEOUS PLANTS 



241 



in association with other plants from the beach. It grows, often 
in abundance, on nearly all the islands ; but it did not come under 
my notice either on Round Cay or on Eastern Cay. Its absence 
from the last-named island, which is the most weatherly of the group, 
may be partly due to its use for firewood by visiting parties, either 
from Grand Turk or from passing schooners, since it thrives on the 
neighbouring Pear Cay, which from the difficulty of landing is much 
less frequently visited. But it may be that hurricanes have assisted 
in its banishment from this cay, as is illustrated by the destruction 
executed amongst its numbers on Greater Sand Cay, as noticed below. 
On Pear Cay it displayed a singular adaptation to the wind-pressure, 
the trunk and primary branches being prone and rooting in the sand, 
whilst the leafy branches alone rose erect three or four feet into the 
air. On Greater Sand Cay I found it fairly well distributed in 
February 1911 ; but my boatmen told me that before the last 
hurricane of 1908 it was much more frequent — a statement confirmed 
by the number of dead prostrate trunks still to be seen on the surface 
over the island, the material being utilised for firewood by small 
sailing craft trading in these seas. The shrub is frequent around 
the coasts of Grand Turk, and in places where the beach vegetation 
borders on the mangrove belt one may sometimes see a curious 
intermingling of the plants of the two formations, Suriana maritima 
with other beach plants growing amongst the mangroves. Though 
preferring a sandy soil, where it grows in colonies, the plant also 
grows well on rocky ground, but only as individuals. 

On the Turks Islands there is evidently from some cause or another 
great loss of seeds. In two localities I found that 95 per cent, of 
the seeds or seed-like fruits gathered from the plants were empty, 
whilst of those picked up from the sand beneath the bushes 30 to 
40 per cent, had sound kernels. The seeds, which are about 3J mm. 
long and broadly conical, have a dark wrinkled hairy skin, which, 
however, they soon lose in the beach- drift, and then they are about 
3 mm. in size and have a smooth reddish surface. In appearance 
they look a little like grape-seeds, and no doubt their hardness 
might fit them for dispersal in the stomachs of birds; but their 
great floating powers offer a much readier explanation of the world- 
wide distribution of the species. Dr. Millspaugh regards the seeds 
as dispersed through the medium of the feet of sea-birds ; but the 
currents aided by the drifting log and floating pumice have doubtless 
done most of the work of distribution. There is nothing in the 
character of the dryish fruits on the plant to attract frugivorous 
birds. 

Hemsley in his list of plants dispersed by oceanic currents includes 
this species (Chall. Bot., I., 42, 48); and Schimper, who especially 
investigated the buoyancy of the seeds, came to the same conclusion. 
I may add that the term " nucule is applied to the seed-like fruits ; 
but they are for purposes of distribution " seeds," and I will follow 
Schimper in this respect. They lie in numbers on the sand near the 
shrubs; and in the Turks Islands they are prominent amongst the 
small drift derived from local plants and sorted out on the beach by 
wind and wave. In this fine drift the seed-like fruits of Suriana 

R 



242 PLANTS, SEEDS, AND CURRENTS 



maritima are associated with the pyrenes of Tournefortia gnaphalodes, 
the seeds of Ipomcea, the " stones " of Sccevola Plumieri, and well- 
rounded small pumice pebbles, 5 to 12 mm. in size. 

These seeds, as I have said, could readily be carried in the crevices 
of floating logs, or in the cavities of floating pumice, such as is 
stranded on the beaches of tropical regions all over the world. But 
it is on their great floating powers, which fit them for dispersal by 
currents, that we must mainly rely. Neither the kernel nor its 
hard covering has any buoyancy, the floating power arising, as also 
ascertained by Schimper (p. 163), from the unfilled space in the seed- 
cavity. In my paper on the plants of Keeling Atoll I refer to some 
experiments there made which only indicated a capacity of floating 
between two and six days in sea- water ; but as the seeds are described 
as rather soft, it is evident that they were immature. Schimper in 
an experiment made at Bonn (p. 165) kept the seeds afloat in salt- 
water for nearly five months (143 days) ; and my experiments in 
Jamaica and the Turks Islands point in the same direction. Thus 
in Jamaica some seeds which had been floating in sea- water for seven 
weeks were quite sound at the close of the experiment. In the 
Turks Islands I placed sixty seeds in sea- water and after nine weeks 
forty-five were floating buoyantly, and would evidently have floated 
for a much longer period. Of the seeds that sank nearly all were 
empty; whilst of those that remained afloat nearly all had dry 
sound kernels and dry cavities. 

Swietenia mahagoni, Jacq. (Mahogany) 

In one's inability to explain its mode of dispersal over the West 
Indian area and the mainland of tropical America, this tree must be 
typical of many other trees of the forests of this region. Having 
made a special study of the fruit in Jamaica, the results of which 
are given in my work on Seeds and Fruits, I here give a few remarks 
on the plant from the standpoint of dispersal. 

Belonging to a genus of only three or four species that are restricted 
to the tropics of the New World, this tree does not raise awkward 
questions, such as are presented by genera common to the eastern 
and western hemispheres. Yet queries almost as difficult to answer 
are implied in its occurrence in the larger West Indian islands. 
Its distribution in South Florida, Mexico, Central America, and Peru 
may be a matter of the continuity of the land-surface, and there is 
much, as far as the plants of the Greater Antilles are concerned, 
to support the contention of the geologist that with those large islands 
in past ages distribution was also a matter of the continuity of the 
land-surface. The occurrence of the Mahogany tree in the Greater 
Antilles and in most of the larger islands of the Bahamas suggests 
questions that are concerned with former continental connections 
rather than with means of dispersal. 

The large winged seeds, two and a quarter inches in length, that 
are freed by the dehiscence of the capsule, are quite unfitted for 
transport by the currents. In experiments they can float a week 
or two; but they absorb sea- water and become sodden and dead, 



MISCELLANEOUS PLANTS 



243 



and they are much too fragile for transport over the sea. It is 
possible that strong winds might carry the seeds some distance; 
but experiment showed that this would not be greater than 100 
feet in a moderate gale. 

Symphonia globulifera (L. fil.) 
(syn. Moronobea coccinea, Aubl. Mart.) 

This West African tree of Upper and Lower Guinea is found in 
the New World in Jamaica, Dominica, Trinidad, Guiana, North 
Brazil, Panama, etc. Its station is by the riverside in mountain 
woods, and in the swampy ground bordering estuaries, but above 
the mangrove formation. In Jamaica I observed it flourishing at 
the waterside on the banks of the Black River estuary ; and accord- 
ing to Forrest Shreve, as quoted by Harshberger (p. 679), it grows 
in the forests of the Blue Mountain Range, forming with Calophyllum 
calaba and other trees closed arches over the rivers. The genus 
has a remarkable distribution, though it may be in part explained 
by our better acquaintance with the floras of some localities than 
of others. Of its dozen or more known species nearly all are peculiar 
to Madagascar; but two are West African, and one of these, S. 
globulifera, is the widely spread New World species that we are now 
considering. 

Its germinating seeds occurred in abundance in the floating drift 
of the Black River estuary. In Jamaica it is known as " Hog-gum " 
or " Boar- wood." Its softish, baccate fruits, which have a yellow 
juice, are one-and-a-half to one-and-three-quarters of an inch long, and 
hold from one to three seeds, one to one-and-a-quarter inch in length, 
which are at first fleshy and afterwards tough and flexible. The 
mature seeds, when freed by the decay or breaking down of the fruit, 
are not in any way protected by their coverings against drying 
or against the penetration of water; and when removed from the 
fruit they shrink greatly. Their readiness to germinate, whilst 
afloat in the Black River, is thus explained ; and I may state that 
quite 95 per cent, of the seeds there observed were germinating. 

The seed presents the structure characteristic of several other 
genera of the Guttiferce, a structure also illustrated in the Barringtonice. 
There is a central axis separated from the outer thick portion by 
a thin layer of vascular tissue (Mirbel's membrane), which becomes 
wavy or crumpled in the drying seed. The cotyledons are either 
absent or are represented by minute scales, the seed being, therefore, 
merely an enlarged hypocotyl. 

When we reflect on the unprotected condition of the fruit and its 
seeds, on the fleeting vitality of the seeds, on their readiness to 
germinate when afloat in river-drift, and on the fate that must 
await them when they reach the sea, it is not possible to find an 
explanation of the plant's distribution on the opposite sides of the 
Atlantic in dispersal by currents; and it would be equally futile 
to look to the agency of birds. We may even go further and hold 
that the seeds are not even suited for inter-island dispersal by either 
agency in the West Indian region. Taking the arrangement of 



244 PLANTS, SEEDS, AND CURRENTS 



land and sea as it is at present, the distribution of this tree offers 
one of the most difficult problems dealt with in these pages. 

Thespesia populnea, Corr. 

This tree has presented itself to me as a littoral plant in several 
parts of the tropical zone, namely, in Hawaii, Fiji, the Solomon 
Islands, Keeling Atoll, and in different islands of the West Indies. 
Its distribution over the tropics of the Old World and its mode of 
dispersal by currents are discussed in my book on Plant Dispersal ; 
but I did not there regard it as belonging to the New World, being 
guided in this matter by Bentham, who in his Flora Australiensis 
regards it as introduced into America. However, there can be 
little doubt that it behaves in the West Indies as an indigenous 
plant ; and, considering its great capacity for dispersal by currents, 
there seems in the light of more recent investigations but small 
reason for the refusal of its proper place in the flora of the New 
World. " Quod credere vix possum " is Urban' s opinion concerning 
the belief of botanists that it has been introduced into America (Symb. 
Antill., IV., 401). If the distribution of the genus given in the Index 
Kewensis offers a clue, the New W T orld can almost make an equal 
claim to be the home of this tree. Of the seven other species there 
named, three are peculiar to Mexico, the West Indies, and Brazil, 
respectively ; one is only found in Africa ; and three are confined to 
Malaya. It is, however, quite possible that in some distant age 
the tree reached the New World from tropical W^est Africa, where 
it is now at home, since the seeds could have been readily carried 
across to Brazil in the Main Equatorial Current. 

It is distributed over the Greater and Lesser Antilles and is found 
in Trinidad (Hart). I especially observed it in St. Croix, Jamaica, 
Grenada, Tobago, and the Turks Islands. In order to prove that 
it behaves as an indigenous shore tree in the West Indies it is of 
importance to name its associates. I found it thriving at the beach 
border on St. Croix in the company of such characteristic littoral 
trees and shrubs, as Coccoloba uvifera, Guilandina bonducella, and 
Hippomane mancinella. Harshberger states that on St. Croix and 
the Virgin Islands it is one of the Coccoloba-Hippomane association, 
the formation of trees and shrubs that immediately lines the beaches 
(p. 686). 

Grisebach speaks of it as growing along the sea-coast of Jamaica, 
and I made notes of its associates in different localities on the shores 
of that island. On the beaches of the Black River district it was 
associated with Coccoloba uvifera, Ecastaphyllum brownei, and 
Guilandina bonducella. In the Savanna-la-mar district a mangrove 
fringe often skirts the low sandy shores, and on the beach behind 
it this tree thrives in the society of Guilandina bonducella, Coccoloba 
uvifera, and Conocarpus erectus, one of the most typical strand 
shrubs of the West Indies. It is associated with the same three 
plants on the borders of the beaches on the north side of the island, 
as at St. Anne's Bay and at White River, and to them we may 
add Sophora tomentosa, another characteristic beach shrub. With 
Coccoloba uvifera it is one of the commonest of the plants bordering 



MISCELLANEOUS PLANTS 



245 



the beaches along the east coast of Tobago ; and in the company 
of the same plant together with Guilandina bonducella and Hippo- 
mane mancinella it grows at the margin of the beach south of St. 
George's Harbour in Grenada. 

There can, therefore, be but little doubt that Thespesia populnea 
behaves like an indigenous strand plant in the West Indies. If 
its exclusion from the proper flora of the New World is based on the 
assumption that the genus has its home in the eastern hemisphere, 
then we should have to exclude such a typical West Indian beach 
plant as Sccevola Plumieri and such representative West Indian 
swamp plants as Rhizophora mangle and Carapa guianensis. 

Against the view that it is truly American are to be urged the 
facts that the tree has not established itself amongst the new vegeta- 
tion of the Florida sand-keys and is regarded as introduced into 
Bermuda (Chall. Bot., II., 22). It is, however, widely spread over the 
Pacific, occurring in some of the most remote islands; and it is 
difficult to imagine how a characteristic shore tree that is of no great 
use to man and is exceptionally suited for dispersal by currents 
could owe its wide distribution, except in a secondary sense, to 
human agency. 

In the Turks Islands the tree gave me the impression of being 
indigenous, though now it could merely be viewed in the light of 
a survival, since it came under my notice only in the northern part 
of the island of Grand Turk. Here it grows gregariously inland 
on one side of the hollow known as the North Wells, but it also grows 
on the borders of the neighbouring coast. I should imagine that 
originally the tree thrived around the lagoons on the beach behind 
the mangroves, as it often does in the Pacific. In Grand Turk and 
Salt Cay the salt industry has led to the destruction of most of the 
original vegetation on the lagoon shores, and Thespesia populnea 
was probably involved in this clearance. 

In the West Indies one not uncommonly finds Nature engaged in 
distributing this plant. The dried baccate capsules and the seeds 
are not infrequent in beach-drift, the fruits liberating by their decay 
the buoyant seeds, which are readily swept off by the waves. In 
some localities in Jamaica I noticed seedlings growing freely in the 
stranded drift. 

It is strange that notwithstanding its capacity for dispersal by 
currents this tree is stated by Lefroy to have been introduced by 
man into the Bermudas (Chall. Bot., II., 22). In this matter it is in 
the same category as Hibiscus tiliaceus, which, as before pointed out, 
is not included in the indigenous flora. In many respects, as in 
its general distribution as a littoral tree in the warm regions of the 
globe, in its fitness for dispersal by currents, and in the wide preva- 
lence of the same native name in the Pacific islands, it raises the same 
issues as Hibiscus tiliaceus ; but there is this difference, that it is 
not of such great use to man, at least among the Pacific islanders, 
and the uncertainty whether it owes much to human agency in its 
distribution, a matter to which Hemsley refers (Chall. Bot., IV., 235), 
is for this reason more pronounced than with the other tree. 

Since I did not deal connectedly with this tree in my previous 



246 PLANTS, SEEDS, AND CURRENTS 



work on the Pacific, I will go briefly over the ground there traversed 
as regards its distribution and modes of dispersal, supplementing 
my remarks with additional observations and reflections and directing 
them towards the elucidation of the problem connected with the 
intervention of man. It resembles Hibiscus tiliaceus closely in its 
general distribution, accompanying it as a common seashore tree 
throughout the archipelagos of the tropical Pacific, in North Australia, 
in Indo-Malaya, in the islands of the Indian Ocean, on both coasts 
of Africa, and in the West Indies ; but, as far as I know, only Hibiscus 
tiliaceus has been recorded from the Pacific coasts of America, 
though it is very probable that Thespesia populnea also grows there. 

The testimony of botanists in the Pacific islands as to its claim 
to be indigenous, that is to say, to have existed there at the time of 
their discovery in the eighteenth century is practically unanimous. 
It was found during Cook's voyages by Banks and Solander in the 
Society Islands and by Forster in Easter Island (Seemann, p. 18) ; 
whilst Hillebrand, the authority for the Hawaiian Islands, places it 
with the plants that were introduced by the natives in prehistoric 
times. Hemsley, Burkill, and Reinecke in the case of the Tongan 
and Samoan floras, Cheeseman as concerning Rarotonga, and 
Seemann in respect of Fiji, include the tree amongst the indigenous 
plants without any comment. 

If as Hillebrand claims, and his opinion is always weighty, the 
Polynesians have carried these seeds about with them during their 
oceanic migrations, what, we may ask, were the inducements for them 
to do so ? Though like Hibiscus tiliaceus the tree yields bast fibres 
which are used for cordage in other parts of the world, it does not 
seem, according to Cheeseman, Hillebrand, Reinecke, Seemann, 
etc., that the Polynesians and Fijians utilised it for this purpose. 
In fact, it was for the durability and hardness of its timber that the 
Fijians, Rarotongans, and Samoans chiefly prized it. Hillebrand, 
however, finds sufficient explanation of its wide distribution in the 
Pacific in the veneration paid by the Tahitians and other islanders 
to the tree. 

I am inclined to consider that the Pacific islanders may have 
assisted in the distribution of this tree, but not to the extent in which 
they aided the dispersal of its frequent associate on the seashore, 
Hibiscus tiliaceus. But whatever was accomplished in this direction 
by man was probably carried out ages ago. Oliver, in his Flora 
of Tropical Africa (1868-77), considered it as probably distributed 
through cultivation. It is worth noting that another species of 
the genus, Thespesia danis, from east tropical Africa was held sacred 
in the Galla country (Hooker's Icon. Plant., ser. iii., Vol. IV.). Though 
doubtless its presence on isolated oceanic islands in the Pacific is 
usually due to currents, I am inclined to hold that in the case of 
Easter Island, where it was found by Forster in 1773, during Cook's 
second voyage, its existence should be attributed to man. 

We pass on to advocate the claims of the currents in explaining 
the wide range of this coast tree. Hemsley, though regarding it as 
introduced into the New World, ascribes to currents a share in its 
distribution (Chall. Bot., L, 42; IV., 125, 235). My first experiment 



MISCELLANEOUS PLANTS 



247 



on its fitness for dispersal by this agency was made in the Solomon 
Islands in 1883. Since that time I have tested the capacity in the 
Keeling Islands, in Hawaii, Fiji, and other localities {Solomon 
Islands, 1887, p. 305; Journ. Vict. Inst. London, 1889; Plant 
Dispersal, 1906, p. 531), all the experiments giving the same indica- 
tions and culminating in one where, after floating a year in sea- water, 
a seed germinated and developed into a plant. The dried fruits, 
which lie in numbers under the trees, are, as already observed, very 
likely to be swept off the beach by the waves. They float, but in 
time break down, thus liberating the buoyant seeds on which the 
dispersal by currents eventually depends. In the West Indies the 
dried fruits, seeds, and seedlings produced from stranded seeds are 
characteristic of the beach-drift, and the same may be said of the 
Hawaiian Islands. In the Solomon Group I found that this was 
one of the early plants that established themselves on the low sandy 
islets of the coral reefs (Chall. Bot., IV., 309). In the Marquesas, 
according to Jouan, it is only found on the seashores in places to 
which the waves could have conveyed the seeds (Ibid., IV., 125). 
In my Victoria Institute paper above quoted good reasons are given 
for the belief that the Keeling Islands possessed the tree at the 
time of their first occupation by white men about 1825, and that 
they received it with many other of their shore plants through the 
instrumentality of the currents. 

The indications of the foregoing discussion are that whilst, as 
with Hibiscus tiliaceus, man and the currents have each played their 
part in distributing the species, the currents have perhaps had a 
rather more important share in the process than in the case of 
Hibiscus tiliaceus. However, I hope at some future time to discuss 
the distribution and dispersal of Thespesia populnea in greater 
detail. 

ToURNEFORTIA GNAPHALODES, R. Br., and TOURNEFORTIA ARGENTEA, 

Linn. f. 

The distribution of these widely spread littoral species of Tourne- 
fortia raises several of the questions presented by the two shore 
species of Sccevola before dealt with, Sc. Plumieri and Sc. Kcenigii. 
One of them, T. gnaphalodes, is found over the West Indies including 
the Bahamas, in South Florida and the adjacent keys, in Bermuda, 
and on the coasts of Mexico and Yucatan, but not apparently on 
the Pacific coasts of the New World. The other, T. argentea, is 
spread over most of the continental and insular coasts of the Indian 
and Pacific Oceans in warm latitudes. It has also extended from 
the East African to the West African coast, being found on the 
shores of Lower Guinea (Oliver's and Dyer's Flora of Tropical Africa, 
Vol. IV., sect 2, p. 29). Unlike Sccevola, however, the two species 
never meet, being separated from each other by the breadths of the 
Atlantic and Pacific Oceans. We have here also a New World 
and an Old World species dividing the tropical beaches of the globe 
between them, but the American species of Tournefortia is appro, 
priated by the New World, whilst the American species of Sccevola 



248 PLANTS, SEEDS, AND CURRENTS 



occurs on both coasts of Africa. We are thus face to face with 
problems of a different nature. 

This is seemingly not such a well-defined genus as Sccevola. It 
holds more than 120 species, distributed over the tropics and sub- 
tropics of the globe; and since the New World possesses its own 
peculiar species, it may be inferred that Tournefortia gnaphalodes 
could have had an independent origin on this continent. Hemsley 
states that there are several littoral species. One of these, as 
I infer, is T. sarmentosa, Lam., which extends from the Philippines to 
North Australia and occurs also in Mauritius and in the Seychelles 
(Bot. Chall, IV., 168). 

Like the two shore species of Sccevola, those of Tournefortia possess 
fruits endowed with great floating powers, and are thus well fitted 
for dispersal by currents. However, they differ from the Sccevola 
plants in that the fruits of both species exhibit the same type of 
buoyancy. There is a much greater resemblance, both in habit 
and general appearance, between the two shore species of Tournefortia 
than in the case of the other two plants. Covered with hairs, which 
give them a silver-grey hue, these shrubs form a conspicuous feature 
in the shore landscape, their height ranging usually up to five or 
six feet, but much reduced in exposed situations. 

I will now deal more in detail with these two species of Tournefortia 
from the standpoint of dispersal by currents. Both of them possess 
dry drupaceous fruits, measuring about seven millimetres in the 
case of T. gnaphalodes and somewhat less in the case of T. argentea. 
When naturally dried, these fruits separate with a little pressure into 
two hemispherical pyrenes, and it is in this condition, but bared of 
their outer dark skin, that they usually occur in the old drift of beaches. 
Each pyrene displays a suber-like exocarp, in which lies imbedded a 
small two-celled stone, each cell usually containing a seed. Deprived 
of its outer covering the stone sinks. 

[Particulars relating to T. argentea will be found in Schimper's 
work on the Indo-Malayan strand flora (p. 174), in my Plant Dispersal 
(p. 108, etc.), and in my paper on Keeling Atoll in the Journal of the 
Victoria Institute (1889)]. 

A familiarity with both species in their homes enables me to treat 
them together here. The fruits of both plants, entire and in halves, 
are of common occurrence in the smaller drift of beaches on which 
they grow. They cover the sand in quantities beneath the bushes, 
and the strong winds scatter them over the beach. So frequent were 
they on some of the beaches of the Turks Islands that they were 
to be noticed in every handful of sand. Under the shrubs they are 
apt to germinate, as was often indicated on Grand Turk by the 
shrivelled projecting radicles that had withered up before they could 
establish themselves in the sand. I noticed both on Keeling Atoll 
and on Grand Turk that the pyrenes are at times mixed with the sand 
washed into the crevices of stranded logs. This matter is especially 
discussed in my paper on Keeling Atoll ; and it is there shown that 
floating pumice must also often assist dispersal in the same manner. 
But although drifting logs and floating pumice often aid dispersal, 
they do not determine it, since the buoyant fruits of these two 



MISCELLANEOUS PLANTS 



249 



species of Tournefortia are of themselves able to cross the broadest 
ocean. 

Whilst my first sea-water flotation experiments, carried out on 
Keeling Atoll and in the Turks Islands, were limited in duration, 
they established the great buoyancy of the fruits of both species of 
Tournefortia, none of them sinking during a period of forty days in 
the case of T. argentea and of sixty days in that of T. gnaphalodes . 
In a subsequent experiment made in England four fruits of T. argentea 
that had been gathered twenty-one months were placed in sea- 
water, all of them floating and displaying sound seeds after a year's 
immersion. In the same way I made a later experiment in England 
on fruits of T. gnaphalodes collected twelve months before. All 
remained afloat and retained sound seeds after six months in sea- 
water. They were sown out, and after a couple of months several 
germinated and produced healthy seedlings. The delay in the 
subsequent germination conveys a warning against expecting quick 
results when testing the germinative capacity of seeds after prolonged 
flotation in sea- water. There was also delay in the case of the fruits 
of T. argentea which had been forty days afloat in sea-water on 
Keeling Atoll. Dr. Treub, Director of the Botanic Gardens of 
Buitenzorg, Java, sowed seven of them in one of his houses, and 
all germinated in the course of two months ( Journ. Vict. Inst. Lond. 
1889). 

However, the dispersal of the fruits of Tournefortia by currents 
is not always so simple as it appears to be. In the case of T. gnapha- 
lodes it was necessary to employ a good number of fruits in my 
experiments, since about half of them had no seeds, the contracted 
seed-cavities indicating their early failure. Another influence that 
goes towards reducing the number of fruits effective for dispersal 
is the tendency of the fallen fruits of this plant to germinate unsuc- 
cessfully on the sand beneath the shrub, a matter already mentioned. 
It is thus likely that a large number of the fruits swept off a beach 
by the waves and carried off by the currents may be ineffective for 
purposes of dispersal. 

With reference to the distribution of Tournefortia gnaphalodes 
in the ten islands of the Turks Group, it may be said that the plant 
came under my notice on all of them except Cotton Cay; but it is 
highly probable that it occurs on that island also, as my examination 
of it was incomplete. In the two largest islands of Grand Turk and 
Salt Cay it grows in quantity, both on the edge of the beaches and 
on the sandy belts in the rear. On Grand Turk it grows around the 
greater portion of the island, and is especially abundant along the 
length of the weather or east side. But it thrives almost as well 
on the rocky surfaces of small cays, such as Penniston, Long, and 
Pear Cays, where sandy beaches are either scanty or absent. Whilst 
it grows over the surface of such small rocky cays, which are from fifty 
to a hundred yards in width and from twenty-five to thirty-five feet 
in height, it rarely strays far from the vicinity of the beach in the 
larger islands, and does not usually climb far up their slopes. How- 
ever, it grows on the sandy top of Round Cay, which, though forty- 
five feet in height, is the smallest of the islands. In islands, like 



250 PLANTS, SEEDS, AND CURRENTS 



Pear Cay and Eastern Cay, which are exposed to the full force of the 
strong winds, the main stem lies prone and roots in the sand, only the 
primary branches rising erect into the air (see Note 3 of the Appendix). 

From Mr. Lansing's methodical examination of the Florida sand- 
keys west of Key West, we are able to form an idea of the relative 
abundance of Tournefortia gnaphalodes in comparison with the other 
plants, the flora being almost entirely littoral and in many respects 
identical with the shore flora of the Turks Islands. Of the nineteen 
keys described, those occupied alone by mangrove colonies being 
excluded, nine possessed this plant, which, though nowhere abundant, 
is evidently fairly well distributed over this region. Yet, although 
better represented than Sccevola Plumieri, which was found on only 
four of the keys, in no single key did it form a predominant feature 
of the vegetation. In five cases it was either scanty or very scanty, 
and in the other keys it grew in moderate amount. 

From the data given by Grisebach, Harshberger, Millspaugh, 
Urban, and others, it is evident that the currents have distributed 
Tournefortia gnaphalodes all over the West Indian islands, both large 
and small, from Cuba, Jamaica, and the Bahamas to Barbados 
and St. Vincent. I have no information relating to its occurrence 
on the mainland of South America; but its ability to establish 
itself on the most isolated islands is indicated by its existence on 
Grand Cayman and the Alacran Shoals (Millspaugh). Though most 
characteristic of the vegetation bordering the sandy beaches, it is 
frequently to be found on a rocky shore of calcareous formation. 
It is a plant that prefers coasts fully exposed to wind and wave, 
and I have shown in Note 3 of the Appendix how well it adapts its 
growth to the wind-pressure. Dr. Millspaugh, who had an extensive 
acquaintance with it in the West Indies, states that it prefers a 
station " on the beach line facing the open sea " (Plant. TJtow.). 
In this respect it resembles T. argentea its sister species of the Pacific 
islands, both plants on account of their hardy nature being amongst 
the first shrubs to establish themselves on a newly formed coral-sand 
key. 

Some of the results of the foregoing comparison of these two 
shore species of Tournefortia are tabulated in the table on p. 251. 

Vigna luteola, Benth. 

In my volume on Plant Dispersal I deal with Vigna lutea, A. Gray, 
a common strand species in the tropics of both hemispheres, but, 
as it would appear, most characteristic of the Old World. I was 
familiar with it amongst the beach plants of Hawaii and Fiji. Its 
small seeds, 5 or 6 mm. long, were frequent in the beach-drift of those 
groups, and also in the floating drift of Fijian rivers. Experiments 
showed that they can float for months unharmed in sea- water. 

Widely spread in the warm parts of the New World is a sister 
species, Vigna luteola, Benth. In its littoral station, in its general 
habit, and in the buoyancy of its seeds, its behaviour is similar to 
the other species. It has a very wide distribution in the New World. 
According to Hemsley and Grisebach, it ranges from Carolina and 



MISCELLANEOUS PLANTS 



251 



Texas to Peru and Chile on the Pacific side and as far south as Buenos 
Ayres on the Atlantic side ; and in the Old World, as we learn also 
from Hemsley (Bot. Chall. Exped., II., 29) as well as from Oliver 
(Flora of Tropical Africa, II., 206), it is found on both coasts of Africa 
and in Australia. It is widely dispersed in the West Indies. Grise- 
bach gives Jamaica, Antigua, Dominica, and St. Vincent as its 
homes. Millspaugh (Plant. Utow., I., 53) gives Porto Rico, Jamaica 
(Port Antonio), and the Cayman Islands. In Jamaica I noticed it 
at Port Antonio, St. Anne's Bay, and at Black River. It is not 



Tabulated Results of the Comparison op Tournefortia gnafhalodes, R. Br., 

AND T OVRNEFORTIA ARGENTEA, Linn. f. 





Tournefortia gnaphalodes 


Tournefortia argentea 


Main facts of 
distribution. 


American shores of the 
tropical and subtropical At- 
lantic, including the West 
Indies, South Florida, and the 
Bermudas. 


Tropical, continental, and in- 
sular shores of the Indian and 
Pacific Oceans, excluding the 
Pacific coast of America ; also 
on coast of tropical West 
Africa. 


Fruit-characters. 


Dry drupaceous fruit, about 
7 mm., separating into two 
hemispherical pyrenes, each 
pyrene displaying a small 
two -celled stone (a seed in 
each cell) imbedded in a cork- 
like exocarp. 


Similar to the other species, 
except that the fruit is rather 
smaller. 


Buoyancy of 
fruits in sea -water. 


Float for months with seeds 
unharmed, none of them sink- 
ing. 


Float for months without 
injury to the seed, none of 
them sinking. 


Cause of the 
floating capacity. 


The buoyancy is due to the 
cork-like exocarp, the stone 
having no independent float- 
ing power. 


The same as with the other 
species. 


Probable home 
of the species be- 
fore buoyancy was 
acquired. 


In the tropics of the New 
World. 


In the tropics of the Old 
World. 


Subsidiary dis- 
persal agencies. 


Birds, drift-wood and pum- 
ice. 


Birds, drift-wood and pum- 
ice. 



mentioned in Hart's " Herbarium List " for Trinidad ; but I found it 
on the south coast of that island. It is also included in the Bermudian 
flora. 

Hemsley says that it frequents brackish marshes on the seashore, 
and Grisebach states that it is common in Jamaica in this station. 
At Port Antonio I found it thriving in wet places on the beach. 
At St. Anne's Bay it grew on the beach ; and at Black River it was 
scrambling over the reeds and other vegetation within the mouth 
of the estuary. On Porto Rico, Millspaugh described it as " rising 
free among high reeds and grasses " (Ibid.). In Trinidad I found 



252 PLANTS, SEEDS, AND CURRENTS 



it on the beach. In the delta of the Mississippi it grows in great 
luxuriance, giving its character and name to the plant-association 
that clothes the higher portions of the alluvial banks between the 
" passes " or mouths of that river : here, clambering amongst the 
canes of Phragmites communis it forms an almost impenetrable 
thicket (Harshberger, Phyt. Survey, N. America, pp. 216, 444, 
under Vigna glabra, a synonym). 

The seeds of Vigna luteola, which are rather smaller than those 
of V. lutea, float for a long time in sea- water. Some, which had been 
seven weeks afloat in one of my experiments, germinated freely 
afterwards. They help to form the smaller drift of beaches, as I 
noticed at Trinidad. Amongst the floating drift of the estuary of 
the Guayas River in Ecuador, I collected a number of sound seeds 
of a species of Vigna, apparently those of V. luteola. 

The cause of the floating capacity of the seeds of both Vigna lutea 
and V. luteola lies in a large central cavity between the cotyledons, 
the materials composing the seed having no independent buoyancy, 
a matter dealt with for the first species in my previous book (p. 106). 
The genus holds about fifty known species, spread over the warm 
regions of the Old and New World; and it would be important to 
determine whether it follows the rule laid down in my earlier work, 
that when a genus possesses both littoral and inland species only 
the seeds or fruits of the shore species float. In the case of the 
Hawaiian representatives of the genus the possibility was there 
pointed out (p. 139) that the two endemic inland species were de- 
rived from the coast species (V. lutea). The genus, it may be added, 
offers many interesting problems for the consideration of the student 
of distribution. 

XlMENIA AMERICANA, L. 

The writer made the acquaintance of this shrub or tree amongst 
the littoral plants of Fiji, where its means of dispersal were investi- 
gated, the results being given in his previous work on the Pacific. 
Like the species of Scazvola and Cassytha that figure in the strand 
floras all round the tropics, it can be dispersed in two ways, by birds 
and by currents. Its drupaceous fruits are known to be distributed 
by fruit-pigeons (Chall. Bot., L, 46); whilst the stones are able, as 
I ascertained, to float in sea- water for months. But since the fruits 
were rarely represented in the beach-drift, it was assumed that bird 
agency has been predominant in the Pacific (Plant Dispersal, p. 113). 

Although, as Hemsley observes (Chall. Bot., IV., 132), it is a mari- 
time shrub throughout the tropics of both hemispheres, it may 
extend inland — a behaviour which it most frequently exhibits in the 
New World. It has been recorded from Tahiti, Samoa, Tonga, 
Fiji, from the islands of the Western Pacific, from North Australia, 
Malaya, both coasts of Africa, and both coasts of the New World. 
Its usual place among the trees and shrubs lining the beaches of the 
Old World seems often to be abandoned, as just remarked, for an 
inland station in the tropics of America. Though it is frequent 
in the interior of South Florida, it has not established itself amongst 
the characteristic littoral vegetation of the coasts or of the sand-keys. 



MISCELLANEOUS PLANTS 



253 



Whilst it is a plant of the beach and of the dunes on the coasts of 
Cuba (Harshberger, p. 673), it seems to be most characteristic of 
inland districts in Jamaica, occurring, as we learn from the work 
of Fawcett and Rendle, at heights of from 2000 to 3000 feet. See- 
mann, however, observes that it is common on the sea-beach on the 
Pacific side of the Panama Isthmus (Bot. Voy. H.M.S. Herald). 
Whilst its range is said to cover the region between South Florida 
and Buenos Ayres. its distribution seems to be fitful in the West 
Indies, and I find no reference to it in my notebooks. 

It would seem that in the New as in the Old World the fruit- 
eating pigeons have taken a more active part in its dispersal than 
the currents. Reference may here be made to the fact that this 
is one of the plants that established themselves on Verlaten Island 
after the complete destruction of its vegetation by the great eruption 
of the neighbouring island of Krakatau in 1883. It was found there 
by Ernst and his party in 1906 (Ernst's New Flora of Krakatau, 

P- 37 )' ... 

The distribution of the species of Ximenia, only five being known, 
is suggestive of a genus that owes its representation in both the 
New and the Old World to its original dispersion from a common 
centre in high northern latitudes in an age when warm climatic 
conditions prevailed in those regions. It seems difficult to look for 
any other satisfactory explanation in the case of a genus which has 
one species that is found round the tropical zone, a second confined 
to Mexico, a third to Brazil, a fourth to South Africa, and a fifth 
to New Caledonia. Yet alternative explanations are possible, 
though not necessarily hostile to Dyer's hypothesis, even though we 
cannot regard them with approval. Thus, one may regard all the 
localised species as derivatives of the plant that ranges round the 
tropical zone. From this point of view it might be supposed that 
Ximenia americana, in dropping species, so to speak, in different 
parts of its range, has played on a large scale the role of a highly 
variable polymorphous species in the Pacific archipelagos. Here 
a solitary species, the sole representative of its genus and ranging 
over the tropical Pacific, becomes ultimately in each group of islands 
the parent of a number of peculiar species, the same process being 
also exemplified in the individual groups (Plant Dispersal, p. 333, 
etc.). Nevertheless, such an explanation would not account for the 
original occurrence of the parent species in the ocean-severed regions 
of the tropics. Either we must regard it as having travelled from 
its birthplace in the tropics around the globe through the agency 
of birds and currents, or we must view it as having been originally 
spread over the diverging land-masses of the globe from a common 
centre in the north. 



CHAPTER XI 



THE GENERAL . CHARACTERS AND GEOLOGICAL STRUCTURE OF THE 

TURKS ISLANDS 1 

The Turks Islands, well known on account of the salt industry 
that has been long established there, are situated on one of the level 
summits of a great submarine mountain range rising up from depths 
of 2000 fathoms and over. The long and narrow bank on which the 
ten islands lie is about thirty-seven miles long, as limited by the 
100-fathom line. The depth of water covering the bank does not 
generally exceed ten or eleven fathoms, and is often only three or 
four fathoms; and so rapid is the submarine slope that, if limited 
by the fifteen-fathom line, the bank would possess much the same 
dimensions. 

Geographically this group forms the south-eastern extreme of the 
Bahamas. Botanically it belongs to the Bahamian region, and 
geologically its structure is that of the same archipelago, the familiar 
aeolian formation of the Bahamas here prevailing. The islands or 
cays are low in elevation, none of them reaching 100 feet in height, 
the highest (Eastern Cay) being ninety-six feet, whilst the lowest 
(Long Cay and Penniston Cays) do not exceed thirty feet. They are 
usually long and narrow, and vary in length from five and a half 
miles in the case of Grand Turk to less than 200 yards in that of 
Round Cay. 

The general characters of this small group are those of the numerous 
islands of the great archipelago of the Bahamas, all of which rise 
from banks that are covered by a few fathoms of water. These 
banks are the flat summits of a lofty range of submarine mountains 
which terminate abruptly near the surface. Rising from the ocean's 
depths of 2000 fathoms and more at the eastern end, the banks are 
separated at the western extremity from the Florida coasts by 
depths of about 400 fathoms. The 100-fathom line surrounds the 
islands and reefs of the Little Bahama Bank, and a similar line 
includes those of the Great Bahama Bank, with intervening depths 
of less than 300 fathoms, the isolation of the banks increasing as we 
go east, depths of 1000 to 2000 fathoms dividing those from which 

1 This chapter was mainly written nearly four years ago, when the author was 
only acquainted with the monograph of A. Agassiz on the Bahamas. Since it has 
been in type he has enjoyed the privilege of communication with Dr. Vaughan, who 
has recently investigated the western Bahamas. His conclusions are of great 
importance; but the writer has been obliged to deal with them in Note 39 of the 
Appendix. 

254 



Turks Islands 

{Adapted from Admiralty Chart 1266) 

Heights in feet thus W 

Soundings in fathoms thus 40> 
When no bottom was found, thus. Jo 



Scale of Sea Miles 



15 /140 



765 



S7 sQPf* ■■ 



13 A^q 

140 



Grand IbrikjfflWJ* TTJRKS ISLANDS 



ZesserStm— . 
784 (awash) 

Entrance to / pg l„„ 
JBanks West jinchf>. c :'%.-> G&£P*3C&&\%£\ „ ^ 

Salt 

(62) 



5 fr-'ir 
iJifir.: ^ (40) 7 




* 13 
9 ^SmUhJ^y 



k 12 / 
\0 Endy 'mion 

}" J 7 K / 



fl2 l7/\_ 

■ key 70 

ISO 



13, 

"iSo 



70 . 



50 

4:%%$<5-o 



Jus**** 



150! M 



246 



s'6) 



MO U CHOI R 
- BANK 



71° 



Jatm-Barfliolomevr & Co. ,113x1? 




\ 



STRUCTURE OF THE TURKS ISLANDS 255 



the eastern islands rise. All the islands are of moderate elevation, 
Cat Island displaying the greatest height of about 400 feet ; but their 
average height would not amount to half this elevation, and large 
areas of some islands are not removed many feet above the sea. 

Whilst viewed orographically the Bahamian banks are connected 
at their western end with the Florida region and project at their 
eastern end into the ocean's depths, they present a similar relation 
with the Greater Antilles. This connection becomes more and more 
dissevered as we proceed from west to east, depths of rather under 
300 fathoms dividing the Great Bahama Bank from the north coast 
of Cuba, whilst depths of 2000 fathoms and over separate the eastern 
banks, on which the Turks and Caicos Islands lie, from the north 
coast of Hispaniola. Trending eastward from the Turks Bank is the 
line of the Mouchoir, Silver, and Navidad Shoals, which are sur- 
rounded on the north, east, and south sides by depths of 2000 to 
3000 fathoms. On the north side of the Bahamian archipelago the 
submarine slopes descend to depths of 2000 fathoms a few miles 
from the shore. 

Some curious considerations offer themselves when we reflect on 
the present and past conditions of the Bahamas, of which the Turks 
Islands form a part, considerations that have a bearing on the 
origin of the geological structure and of the floral characters of the 
whole region. It may be that in Miocene times, when the Florida 
peninsula was under the waves, the Bahamas were the Laccadives 
and the Maldives of the coral-reef region of the Atlantic. Dana in 
his Corals and Coral Islands (p. 213) gives vent to a suspicion of this 
kind ; but he did not follow it up, and contented himself with noting 
the analogy between the eastern and western ranges of land on the 
Great Bahama Bank and the opposite sides of the Maldive Group. 
However, the coral reef makes a peremptory demand to be called 
as a witness in this connection, and for this reason. Only in coral- 
reef regions could we find the conditions that have produced an 
archipelago, several hundred miles in length, consisting of relatively 
low islands that are entirely composed of reef debris and calcareous 
aeolian rocks. In a geographical sense the analogy with the above- 
named archipelagos of atolls in the Indian Ocean is closer than 
would at first appear. The Laccadives would represent the western 
portion of the Bahamas, where the islands come into relation with 
the adjacent continent, and the Maldives would stand for the free 
oceanic eastern portion that protrudes into the ocean's depths. 

In the Bahamas we have an archipelago possessing hundreds of 
islands, large and small; and yet along its length of 600 miles and 
more there is not an island that is more than 400 feet above the sea, 
the majority of them not exceeding half this elevation. Several of 
the eastern islands rise from banks that are the flattened tops of 
submarine mountains starting up some 12,000 feet above the ocean's 
floor. Yet there is relatively little difference in the elevation of the 
islands, and we find this small range in height along the length of 
the archipelago. We have here the anomaly that so exercised 
Darwin's mind in the case of the lines of living atolls in the Indian 
and Pacific Oceans ; that is, a lofty range of submarine mountains, 



256 PLANTS, SEEDS, AND CURRENTS 



rising from the ocean's depths, which along a length of several 
hundred miles exhibit a line of peaks that in all cases end abruptly 
at or near the ocean's surface. The implication is that atolls origin- 
ally crowned the summits of these submerged peaks in Bahamian 
seas, atolls long since overwhelmed by the shifting sand-dune, the 
work of which is presented in the seolian sandstone of our own day. 
But, as in the line of atolls formed by the Laccadive and Maldive 
archipelagos, there is a " continental " end, where the Bahamian 
archipelago abuts on the adjacent continent, and an "oceanic" end, 
where it projects into the ocean's depths. 

The standpoint adopted with regard to the problems offered by the 
Bahamas would, I think, largely depend on whether the investigator 
was familiar with the western or " continental " portion or with the 
eastern or " oceanic " portion. The points of view might differ 
materially. Politically as well as geographically the western area 
is by far the most important ; and from the time of Catesby, nearly 
200 years ago, to that of A. Agassiz in our own day, the experience 
of the west has largely coloured the views of the majority of investi- 
gators. Agassiz, it is true, made a general examination of the 
archipelago; but his acquaintance with the west principally deter- 
mined his views. On the other hand, the present writer's experience 
was limited to a three months' sojourn in the Turks Islands at the 
extreme eastern end of the archipelago, during which period he made 
a fairly detailed examination of all the islands of the little group. 
He may thus claim to be an exponent of the " oceanic " standpoint. 

Much mystery surrounds the history of the Bahamas. The view 
that there are atolls buried beneath the seolian deposits does not 
involve any change of level, since the sand-dune could have effected 
all that we see at present without the assistance of a movement of 
upheaval. When, as with the Turks Islands Bank, the original 
bank was long and narrow, the atoll form of reef would be replaced 
by a reef of similar shape. But on a broad platform, like that pre- 
sented by the neighbouring Caicos Bank, a typical atoll might have 
been formed, of which we may discern the remains now in the broken 
margin of islands and in the extensive flats in the interior of the 
bank that are now covered by only a few feet of water. However 
this may be, all that we see at present could have been produced at 
the existing sea-level. Different periods of upheaval and subsidence 
of the Bahamian area have been postulated by geologists and 
zoologists; but, without entering into matters that are mainly 
inferential, I will at once proceed to refer to the account of these 
islands given by A. Agassiz in his Reconnaissance of the Bahamas 
(Bull. Mus. Comp. Zool. Harvard, 1894), a work from the hand of one 
of the foremost investigators of our time. 

A. Agassiz on the Formation of the Bahamas. — After remark- 
ing that the islands of the Bahamas are from end to end all of seolian 
origin, he thus proceeds — 

" They were formed at a time when the banks up to the ten-fathom 
line must have been one huge irregularly shaped mass of low land, 
the coral sand beaehes of which supplied the material that must 
have built up the successive ranges of low hills which we still find in 



STRUCTURE OF THE TURKS ISLANDS 257 



New Providence, and which are so characteristic of all the ridges of 
the islands of the group. After the formation of the islands came 
an extensive gradual subsidence, which can be estimated at about 
300 feet, and during this subsidence the sea has little by little worn 
away the aeolian hills, leaving only here and there narrow strips of 
land in the shape of the present islands." 

Before I proceed to give in detail the results of my observations 
in the Turks Islands some discussion of the views of Agassiz is 
necessary. He considers that the disintegration of the original land- 
surface is still in progress; but this would be under present-day 
conditions, which would be quite other than those which prevailed 
when the land was being broken up during the movement of sub- 
sidence, and could not safely be employed in illustration of it. In 
this connection he regards the strips of land on the Caicos and Turks 
Banks as representing the last stages in the process of destruction, 
the original condition of those banks being exemplified in the neigh- 
bouring large island of Great Inagua, where the whole area of the 
bank is occupied by land ; whilst the intermediate stage is presented 
in the island of Andros. Another point is that this investigator 
lays no stress on the operation of reclaiming agencies at the present 
time. Here and there a bight or a cove may have been filled in; 
but the prevailing tendency in our own day, as in the past, is (he 
holds) one of destruction. However, as he himself shows, a large 
portion of the island of Grand Turk has been reclaimed by coral- 
growth at the present sea-level; and in general terms he describes 
the islands of the Turks Group as formed in part of aeolian rock and 
in part of shore coral-rock. 

Then again, when he describes the Bahamas as representing the 
results of the breaking up, during a movement of subsidence amount- 
ing to 300 feet, of one huge mass of low land, he could have had in 
his mind only the western portion of the archipelago. The banks 
from which the eastern islands rise must have been isolated through 
the ages. So rapidly do they plunge down into the great depths 
dividing them that an upheaval of 300 feet would add but little to 
their size, and would be far from establishing any connection between 
them. 

Let us take the adjoining banks from which the Turks and Caicos 
Islands rise. They are united under the sea by a " col " covered by 
about 250 fathoms of water, and lying a few miles to the south of 
them. This " col " is the head of a deep submarine valley, running 
north between the two banks along their whole length, which is at 
least about 1500 fathoms deep opposite Grand Turk and about 2000 
fathoms where it debouches on the ocean's floor. A subsidence of 
300 feet (fifty fathoms) could not have effected the separation of 
these two banks, seeing that the " col " was some 1200 feet under 
the sea before it commenced. Moreover, isolated as the two banks 
are from each other, this " col " is in relatively shallow water as 
compared with the ocean depths around them. The great hollow 
that separates them on the south from Hispaniola is 2000 fathoms 
and more in depth. Similar depths of 2000 fathoms isolate the 
Caicos Bank from the neighbouring island of Mariguana, and prob- 



258 PLANTS, SEEDS, AND CURRENTS 



ably also from Great Inagua. To the north of the two banks lies 
the open ocean with a depth of 2000 to 3000 fathoms. 

No soundings in which bottom was obtained are given in the 
Admiralty chart (1266) for the seas dividing the three great banks 
stretching south-east from the Turks Islands, namely, Mouchoir, 
Silver, and Navidad Banks; but it is not improbable that they are 
connected by deeply submerged " necks." Except probably on the 
Turks Island side these three great banks rise up from the ocean 
depths around them. The trench separating them from Hispaniola 
is 2000 fathoms deep, whilst to the north is the open sea, where 
soundings of 3000 fathoms have been obtained. To the east this 
line of banks plunges down in a few miles to depths of over 2000 
fathoms, which increase as we go eastward some forty miles towards 
the Brownson Deep, where depths of 4000 to 4500 fathoms occur. 
From what has been said above it is apparent that the eastern 
extremity of the Bahamian area, including the Caicos and Turks 
Banks with the islands rising from them and the Mouchoir, Silver, 
and Navidad Banks that carry no islands, has been isolated from the 
rest of the region by deep-sea conditions through the ages. As we 
proceed westward the connecting seas become shallower and the 
banks and islands larger; but the process is gradual, and even 
immediately west of the Caicos Bank depths of 1200 to 1800 fathoms 
separate banks and their islands. 

I come now to the reasons assigned by A. Agassiz for assuming a 
subsidence of 300 feet. They are based on the existence of " ocean- 
holes" in the banks. These holes have been sounded to a depth of 
thirty-four fathoms (204 feet) ; and it is to be supposed that in 
estimating the total depression at 300 feet he allowed for the depth 
of water covering the banks. He considers that they were formed 
in the seolian rocks, before the subsidence, by the same agencies that 
produce the present caverns, sinks, blow- holes, etc., in the geolian 
sandstone of the hills. We learn from his maps that these " ocean- 
holes " may pierce the banks to a depth of 200 feet and may be 200 
yards or so in width. I venture to think that this evidence in sup- 
port of a depression of 300 feet is a little hypothetical. In any case, 
the decision must lie with the student of land forms and submarine 
contours, the interpretation of which has become an important 
branch of geological science in recent years. 

The subject of these " blue " or " ocean " holes has evidently 
received much attention from American geologists. Dr. Vaughan 
has recently procured additional information concerning them in the 
North-west Bahamas, and he writes that " on the assumption that 
these holes were subaerially formed, parts of Andros must have once 
stood 192 feet higher than now." Similar but smaller holes, as he 
states, exist in the Miami coast region of Florida. They penetrate 
to a depth of over thirty-five feet a rock floor of oolite lying ten feet 
below low tide, and are regarded as " indicating the presence of 
solution wells " in that formation (Year Book of the Carnegie Institu- 
tion of Washington for 1914 and 1915, No. 13, pp. 227-33; No. 14, 
p. 234). 

This subject raises another important point. An implication of 



STRUCTURE OF THE TURKS ISLANDS 259 



the theory of Agassiz is that the foundations of the aeolian sandstone 
would lie far beneath the surface of the sea. I find no reference in 
his pages to the exposure of any base-rock in this region, and his 
views would expressly exclude the idea of the existence of a founda- 
tion of " reef-rock " at or above the sea-level. In the case of the 
same aeolian formation in the Bermudas, Professors Heilprin and 
Rice lay stress on the exposure of a foundation of reef-rock; but 
Agassiz rejects their interpretation. Naturally, if, as I hold, the 
aeolian deposits of the Bahamas were formed with the sea at its 
present level there would be a base-rock composed of coral-reef 
debris; and it ought to be exposed during the retreating tide, where 
cliffs front the sea. But a little reflection will show that situations 
favouring its exposure would be usually inaccessible on account of 
the breakers and the rollers ever dashing against the base of the 
sea-cliffs. Such an examination would be hazardous in the Turks 
Islands, for the sea is rarely sufficiently quiet on the weather coasts 
of the islands where these sea-cliffs exist. In those places where 
the cliffs lie a little inland, being cut off from the sea by the growth 
of a fringing reef, extensive beaches with the sand piled up against 
the foot of the cliffs would effectually prevent observation. The 
most favourable localities would exist where a line of cliff washed by 
the waves abuts on a beach. Even these do not always permit one's 
approach ; but I found such an accessible spot in the Turks Islands, 
and there was exposed, underlying the aeolian sandstone, a reef-rock 
containing large fragments of corals. 

There are two points connected with these aeolian sandstones to 
which A. Agassiz makes no allusion. The first is that this formation 
seems to be peculiar to the Bahamian and Bermudian regions. 
Calcareous sandstones, formed by the consolidation of wind-blown 
sand derived from coral-reef beaches and composing entire islands, 
are unknown in the great coral-reef regions of the Indian and Pacific 
Oceans. The second point is concerned with the conditions under 
which these aeolian rocks were formed. Their absence, more or less 
complete, from other great coral-reef areas would seem to imply 
that unusual conditions, mainly climatic, prevailed during their 
formation in the Bahamas and in the Bermudas. Both these 
matters are dealt with at the close of the chapter. 

The Author's Observations on the Geological Characters 
of the Turks Islands. — The results are given here exactly in the 
form in which they were written before the author had read the 
memoir of A. Agassiz on the Bahamas. The remarks suggested by 
the perusal of that work have since been intercalated. The sojourn 
of the American naturalist in this group probably did not cover 
more than a week or two ; but he seems to have visited all the islands, 
including those that are most isolated, such as Eastern Cay and 
Greater Sand Cay. Though few details are given by Agassiz, it will 
be seen that the results obtained by the present writer are in general 
agreement with his conclusion that the islands are formed in part of 
aeolian sandstone and in part of shore coral-rock. However, the 
distinction has to be made between the work of the past and of the 
present in describing the formation of these islands. Whilst the 



260 PLANTS, SEEDS, AND CURRENTS 



extensive low sandy tracts, overlying old reef-rock, belong to the 
present, the " nuclei " of seolian sandstone, around which they have 
been formed, belong to the past, a past when probably almost the 
whole of the Turks Bank was occupied by land of seolian formation, 
four-fifths of which have disappeared at the hands of the marine 
and aerial eroding agencies. 

All the ten islands or cays are composed either entirely or in part 
of the seolian sandstone, the growth in size in later times by the 
development of low land around " nuclei " of the seolian rock being 
chiefly characteristic of the larger islands. 

The Molian Sandstone. — This is a white calcareous sandstone of 
the Bahamian oolitic type. Whilst on the exposed surface the 
materials are often cemented into a hard crust, which is some 
inches thick and possesses an almost flinty fracture, they are usually 
loosely compacted beneath, so that the rock readily breaks down 
between the fingers. The crust, however, is generally broken up 
into slabs, as explained below, thus exposing the less consolidated 
rock which, readily disintegrating, has furnished much of the loose 
sand that occurs on the surface of the interior of the larger islands. 
It is as a semi- compacted sandstone that the rock typically presents 
itself ; but in the smaller low flat cays it is the hard crust that attracts 
most notice, and one might imagine that one was dealing in the 
mass with a hard, honeycombed limestone, if the attention was 
confined only to the surface characters. It is in the face of the line 
of bluffs on the east side of Grand Turk and in the coast cliffs of the 
other large cays that this formation is best exposed; but one may 
find good exposures at times in the smallest of the islands when they 
possess any elevation, as on Round Cay. 

This formation sometimes offers itself in thick beds of loosely 
compacted sandstone composed of usually well-rounded grains 
varying from 0*5 to 1*5 mm. in size. At other times the rock is made 
of finer materials, between 0-3 and 0-5 mm. in size and rather more 
consolidated. Such finer sandstones often display a laminated 
structure, the layers being usually horizontal; but they are occa- 
sionally inclined, in which case cross-bedding may at times be 
observed. The hard crust exhibits scattered grains in a compact 
matrix, and has the appearance of a consolidated calcareous ooze; 
but, as is shown below, it has a very different history. All these 
rocks dissolve readily in acid, leaving scarcely any residue. 

Nowhere did I find any marine shells or other marine remains in 
the aeolian rocks. However, on the sandy slopes of Gibb Cay I 
found gathered together on a ledge great numbers of old Bulimoid 
shells of a large species of land-mollusc. Whether they had been 
freed by the disintegration of the sandstone from which the loose 
sand was derived, or whether they represented a molluscan fauna 
that had subsisted on vegetation which had been destroyed by the 
goats, I could not determine. The first explanation seems to be 
most probable, since A. Agassiz (p. 20) remarks that land-shells 
similar to those now living on the islands occur in the seolian rocks 
of the Bahamas. 

We come now to the consideration of the hard surface-crust of the 



STRUCTURE OF THE TURKS ISLANDS 261 



aeolian sandstone, a discussion that will lead up to the treatment of 
the causes of the consolidation of the rock in the mass. The harden- 
ing process of the crust extends to a depth varying usually from 
three to twelve inches. When, as often happens on the lesser cays, 
large level surfaces of the hard crust are fully exposed to the sun's 
heat, the rock becomes fissured in all directions, and the ground 
looks as if it had been irregularly paved. With the continuation 
of the fissuring process and the constant widening of the cracks 
through the weathering agencies, the ground is ultimately strewn 
with slabs of all sizes that generally vary in thickness between three 
and twelve inches and lie in confusion around. All over these 
islands we find in the interior and even at the coast, both on level 
ground and on the tops of the more barren ridges, this slabby broken 
ground in all stages of disruption. The hard crust separates readily 
in large slabs from the underlying loose sandstone. On Penniston 
Cay, a low flat island only thirty feet in height, the hard surface 
crust is in places so much honeycombed and broken up that walking 
is difficult. In other places, again, we have large slabby undulating 
surfaces only in the early stage of the disrupting process, and looking 
more like the top of a lava flow. This hard crust of the seolian 
sandstone has often been described. Alluding to this sandstone, 
A. Agassiz remarks that it "is " covered with a hard ringing crust 
when exposed to the action of the sea or the rains." In this con- 
nection we can here appropriately introduce the fact that it is to 
his celebrated father, L. Agassiz, that we are indebted for the clue 
to the nature of the hardening process that affects the surface of 
the rock. 

The Observations of L. Agassiz on the Salt Key Bank. — 
But the observations of the elder Agassiz, which were published 
about half a century ago in the first volume of the Bulletin of the 
Museum of Comparative Zoology, go further, since they also throw 
light on the conditions under which the consolidation of the mass 
of the formation takes place. They were made on the keys or low 
islands of the Salt Key Bank, which lies between the Great Bahama 
Bank and the coasts of Florida and Cuba. After describing the 
oolitic rock (as he terms it) formed by the consolidation of the 
calcareous sand of the high dunes gathered by the wind, he alludes 
to its being very hard and to its ringing under the hammer, the 
weathered surface being implied. But the clue is afforded in his 
reference to " thin layers of very hard compact limestone, alter- 
nating with the oolitic beds, which have no doubt been formed in 
the same manner as the coating of the pot-holes." 

These pot-holes are described as of two kinds, those of recent and 
those of ancient origin. The first, lying near the water's edge, are 
" mostly clean excavations," being either empty or containing a 
little loose sand or pebbles. The second, ordinarily beyond the 
reach of the tides and the waves, have often been " gradually filled 
with materials identical with those of the older (oolitic) deposits." 
They are " generally lined with coatings of solid, compact, and hard 
limestone, varying from a thin layer to a deposit of several inches 
in thickness. ... It is plain from their structure that these coatings 



262 PLANTS, SEEDS, AND CURRENTS 



are a sub-aerial formation, increasing by the successive accumula- 
tions of limestone particles left upon the older rock by the evapora- 
tion of water thrown upon the Key when the ocean is so violently 
agitated as to dash over the whole Key. Frequently the hollow of 
these coated pot-holes is further filled with consolidated oolite; or 
thin layers of fine-grained oolite alternate with a coat of compact 
limestone, throughout the excavation, which has often been filled 
in this way up to the general level of the surrounding surface. . . ." 
The structure and the mode of filling of these ancient pot-holes are, 
as Agassiz goes on to say, distinctly exhibited in the cases of those 
that have been partially cleared out by the action of storms. 

The account of the keys of the Salt Key Bank is given in full by 
Dana in his Corals and Coral Islands (1872 p. 213,). The elder 
Agassiz supplies an illuminating description of the history of the 
formation of these aeolian rocks on these islands. The bank, covered 
by from four to six fathoms of water, is formed of the " oolitic " 
grains of coral materials mingled with broken shells. Its margin 
is encircled in some places by rocky ridges and in others edged by 
sand-dunes. " A close examination and comparison of the different 
Keys show that these different formations are in fact linked together, 
and represent various stages of the accumulation, consolidation, and 
cementation of the same materials." That the aeolian rocks have 
been formed by the consolidation of the sand-dunes, he has no 
doubt. The sand composing them " must have been blown up by 
the wind, and accumulated in the form of high dunes before it 
became consolidated." This dune-sand is still loose, but, as on 
Salt Key, it shows " here and there a tendency to incrustation at 
the surface." Then in the case of another key, where the aeolian 
sandstone prevails, he says : " It is evident that what is beginning 
on Salt Key has here been completed." All this, it should be noted, 
has been accomplished with the sea at its present level, a matter 
that is dealt with again below. Different localities have their 
individual lessons, and I may here remark that though sand-dunes 
occur in places near the coasts of the larger islands of the Turks 
Group, they very rarely exhibit a tendency to surface-consolidation. 

The Basement of the jEolian Sandstone. — For reasons before 
explained, underlying rocks of a character different from that of the 
aeolian rock are rarely exposed. It has already been observed that 
the claim made by Professors Heilprin and Rice for the existence of a 
basement of old reef-rock in the Bermudas is disallowed by A. Agassiz, 
who regards it as the effect of the action of the sea in cementing the 
strata together and destroying their aeolian structure. But the 
weightiest evidence against him is supplied by his father in the case 
of the islands of the Salt Key Bank. Their foundation is not aeolian 
sandstone, but " a conglomeration of coarser oolitic grains, rounded 
fragments of corals, or broken shells, and even larger pieces of a 
variety of corals and conchs, all the species being those now found 
living on the Bank." Stratification is displayed, the beds dipping 
towards the sea at an angle of about seven degrees. This founda- 
tion never rises above the level of high- water. It is, as the present 
writer will show, but a coarse kind of the " beach-rock " that is 



STRUCTURE OF THE TURKS ISLANDS 263 



exposed between the tide-marks on the sandy islets of coral-reef 
regions all round the tropics, and forms the basement of the islet. 
Upon this foundation are heaped up by the waves, as is described 
by L. Agassiz, masses of sand, broken shells, and fragments of 
corals, which in their turn are covered by the finer sand driven by 
the wind and forming sand-dunes. He does not refer to any ex- 
posure of an actual contact of the aeolian rock with its foundations ; 
but we may infer that they would be the materials heaped up by the 
waves, but more or less consolidated and cemented, and passing 
downward below the high-water level into the basement rock, 
similarly composed of sand, broken shells, and coral debris, that 
constitutes the foundation of the islands. 

It was only in one locality in the Turks Islands that I found a 
good contact-exposure of the rocks underlying the aeolian sandstone. 
This was on the east coast of Greater Sand Cay near its southern 
end. Here, about two or three feet above the high-water level, the 
aeolian rock sometimes passed down into a coral-rag, composed of 
large fragments of massive corals imbedded in a matrix of compacted 
coarse sand, and at other times into an ordinary coarse beach sand- 
rock such as is described below. 

" Beach sand-rock " came under my notice in different islands of 
the Turks Group, as on Grand Turk and Salt Cay. It is character- 
istic of low coral islands all over the tropical Pacific, and doubtless 
is common enough in the Bahamas. It is well described by Dana 
in his Corals and Coral Islands (1872, pp. 152, 184), and I have dealt 
with it in my Geology of the Solomon Islands (1887, p. 84). It is a very 
coarse white sand-rock, and is stratified, the beds dipping seaward 
with the slope of the beach at an angle usually of seven or eight 
degrees. It is composed of coral and shell debris; but many 
characters distinguish it from the aeolian sandstone or drift sand-rock, 
notably the larger proportion of coral debris, the coarseness of the 
constituents, and their great irregularity in size. Sometimes the 
materials forming the beach sand-rock are imperfectly consolidated. 
At others they are firmly cemented into a hard rock with a metallic 
ring ; and when, as is not infrequent, large fragments of corals and 
dead shells are enclosed in the hard matrix it might be termed a 
coral-rag, though reef-rock would perhaps be a more appropriate 
name. The typical rock is exposed between the tide-marks. But 
it is a formation that is only exposed by the removal of the overlying 
loose sands by the waves. Wherever exposed, it is always in process 
of destruction through the action of the sea. I have never seen it 
in process of formation. The conditions under which the stratifica- 
tion and consolidation take place are obscure. Evidently, whether 
as sand-rock or reef-rock, it forms the platform on which islands and 
islets are thrown up by the waves; and it would be on such a 
foundation that the subsequently produced aeolian deposits would 
be based. 

The upshot of the foregoing remarks would appear to be this. If 
there has been an extensive subsidence of 300 feet in the Bahamian 
region since the formation of the aeolian sandstone, as is assumed by 
A. Agassiz, the foundations of the aeolian rock ought to lie far beneath 



264 PLANTS, SEEDS, AND CURRENTS 



the waves. As far as the Turks Islands supplied direct evidence on 
this point, it was to the effect that the aeolian rocks passed downward 
into consolidated reef debris, consisting of coarse sand, dead shells, 
and coral fragments, which had been thrown up on reef-rock at the 
present sea-level. The same inference is to be drawn from the 
observations of L. Agassiz on the islands of the Salt Key Bank. 

The Evidence supplied by Charts of Recent Changes in 
Level in the Bahamas. — Fortunately this matter has received 
considerable attention in one way or another. Looking at the 
evidence supplied by the examination of old maps, particularly that 
obtained by Mr. Tillinghast which is mentioned below, and having 
regard to the unimportant changes that occurred between the 
careful survey of 1834 and the time of his visit in 1893, A. Agassiz 
concludes that " we are warranted in assuming that the configura- 
tion of the Bahamas, as we now know them, does not differ materially 
from that of the Y as de los Lucayos as they were first discovered by 
Columbus." From this we may infer that during a period of 400 
years no great change has occurred in the relations between land and 
sea in this region. 

Mr. Tillinghast carried out his investigations with the idea that 
" an examination of old maps " might reveal a change in the con- 
dition of the Mouchoir, Silver, and Navidad Banks since the time of 
the discovery of the Bahamas " which might be of importance in the 
disputed question of the landfall of Columbus." As a result he 
formed the conclusion, after examining a large number of old charts 
going back to the beginning of the sixteenth century, that " they 
throw more light on the condition of the cartography of the West 
Indies than on any physical change among the islands " (see Notes 
on the Historical Hydrography of the Handkerchief Shoal (Mouchoir 
Bank) in the Bahamas, in the " Library of Harvard University, 
Bibliographical Contributions," No. 14, 1881). 

In this connection A. Agassiz lays stress on the difficulties sur- 
rounding such investigations, and notably the rarity of actual sur- 
veys of these regions. He points out (p. 14) that in the chart of the 
first survey of these three banks at the south-east end of the Bahamas, 
that of Count de Chastenet-Puysegur (1784-7), only shoals and 
banks are drawn. This is interesting as showing that the three 
banks (Mouchoir, Silver, Navidad) bore no islands then as they bear 
no island now. Their stationary condition during the last 200 
years is also indicated by the fact that their shoals and rocks were 
as dangerous to the navigator in the early part of the eighteenth 
century as they are now. The site of a wreck, named " Plate 
Wreck," is marked in some of the old charts on one or other of 
these three banks. Thus it is shown in one of the maps given by 
Catesby in his work on the natural history of Carolina, Florida, and 
the Bahamas (Vol. I., 1731). 

In the British Museum library I came upon an old chart of the 
Turks Islands, which is not included in Tillinghast' s extensive list 
of the early maps of this region. It describes itself as constructed 
from " a survey made in 1753 by the sloops VAigle and V Enter aude 
by order of the French Governor of Hispaniola with improvements 



STRUCTURE OF THE TURKS ISLANDS 265 



from observations made in 1770 in the Sir Edward Hawke, King's 
Schooner." Further details are given in Note 32 of the Appendix; 
but I may say here that it represents the results of a regular survey, 
the three main positions being fixed by astronomical observations, 
the error in longitude being about forty minutes and the errors in 
latitude not exceeding two miles. But, as will be noticed below, 
when discussing the effects of the reclaiming process in these islands, 
the period for comparison is very limited, since the latest Admiralty 
chart of this group is mainly based on the survey of 1830. It is, 
however, permissible to infer on grounds given in the Note that 
there has been extensive shoaling between the islands since the 
French survey, though the depths on the open bank clear of the 
islands experienced but slight change in the interval between the 
middle of the eighteenth and the middle of the nineteenth century. 
Lesser Sand Cay, a sandy islet lying between Cotton Cay and Grand 
Turk, on which plants obtain at times a scanty hold, evidently did 
not exist at the time of the French survey. 

The Degradation of the .ZEolian Sandstone in the Turks 
Islands. — Just as L. Agassiz in the case of the seolian rocks of the 
islands of the Salt Key Bank lays stress on the extensive disintegra- 
tion they are experiencing at the hands of the atmospheric and 
marine agencies, so we may lay emphasis on the same process of 
destruction in the Turks Islands. If Nature busied herself in pro- 
ducing these deposits ages ago, she is not doing so now. There is 
nothing about these formations that is modern. For ages they have 
been exposed to great degradation; but, as we shall see, Nature by 
setting up a reclaiming process is now doing her best to save the 
pieces. In those localities where there is no protecting beach, as in 
the case of the smaller rocky cays and of some of the headlands of 
the larger islands, the full force of the breakers of the open ocean 
is spent in the destruction of the seolian sandstone. Long narrow 
rocky islands, such as Long Cay and Penniston Cay, where there is 
no protection against the breakers, have already been cleft through 
near their extremities. Toney Rock, which lies near Eastern Cay 
and receives the whole brunt of the breakers, represents the last 
stage in the process of destruction. When a beach protects the 
coast, the atmospheric agencies are active in degrading the cliff- 
faces that once were buffeted by the waves. The bluffs, so con- 
spicuous on the eastern side of Grand Turk, are from this cause in 
full retreat landwards. 

The Modern Process of Reclamation of Land from the Sea 
in the Turks Islands. — As already observed, A. Agassiz lays no 
stress on reclaiming agencies in the Bahamas. L. Agassiz, who 
rightly includes the Salt Key Bank in the Bahamian region, refers 
to the " very instructive combination of the phenomena of building 
and destruction " in its shoals and keys. In the Turks Islands 
there exists, side by side with the process of degradation of the 
original land-surface of seolian rock, a process of renovation that 
will ultimately prevail. It is unfortunate that a comparison of the 
old French chart of 1753 with that in present use covers too short a 
period to be of much service to us. The Admiralty chart (No. 1441) 



266 PLANTS, SEEDS, AND CURRENTS 



of the Turks Islands is based on Captain Owen's survey of 1830, 
with additions to 1845 and corrections to 1898 ; whilst the French 
chart is emended from observations made in 1770 in an English 
survey ; so that the period for comparison is limited to sixty years. 
However, as will be shown below, the changes that can be estab- 
lished are all on the side of " gain." The reclaiming process is 
indicated : — 

(a) By the shoaling of the Bank. — Whether we referred to the 
French chart or to the later chart, we should be equally correct in 
saying that the bank from which the Turks Islands rise is covered 
by from ten to eleven fathoms of water in the deeper parts. But 
more than eighty years have elapsed since the last survey, and it is 
evident that the whole bank is shoaling through the growth of coral 
and the accumulation of reef debris. Sandbanks are forming in 
the shallows and are endeavouring to give rise to new islands. One 
such islet, known as Lesser Sand Cay, lies half-way between Grand 
Turk and Cotton Cay. Though well exposed at low-water, it is 
ever shifting its site and changing its form. At times vegetation, 
derived from drift seeds, begins to appear on its surface ; but before 
long this is washed away by the waves. When I knew it in the early 
part of 1911, it was a bare bank of sand not 100 yards in length. 
Yet in time a permanent islet will be established, and a century 
hence it will be well stocked with littoral plants. 

(b) By the throwing up of Protective Beaches and Sandbanks around 
and between the nuclei of JEolian Sandstone. — Yet Nature has other 
ways of reclaiming land from the sea on the bank. After the waves 
have been battering for ages one of these islands of seolian sand- 
stone, she often sets herself to work to save the pieces through the 
growth of corals and the heaping up of sand and other reef debris. 
Let us take the case of Greater Sand Cay, which is about one and a 
half miles in length and elevated some forty feet above the sea. 
We can read its history as we approach it from the northward. In 
the distance it appears as a group of four islets. But as we get 
nearer low connecting strips of land rise above the horizon, and we 
discover that the four islets, as they seemed, form the hummocks, 
or low, mound-like hills, of a single island. The hummocks are 
made of the seolian sandstone, and the low necks that unite them 
are banks of sand. Here it is evident that a long strip of land of 
aeolian rock was first broken up by the action of the sea. But in 
later times, whilst the waves were wearing away the islets, the water 
was shoaling around. Ultimately the energy of the waves was 
chiefly occupied in throwing up protecting beaches and in joining 
the islets by sandbanks. In this way the remains of the original 
island have been preserved, and doubtless the present island will 
continue to increase in extent. The process of joining up the islets 
has evidently been in operation in relatively recent times. In the 
French chart (1753-70) the northern third is represented as separated 
from the rest of the island by a channel 250 or 300 yards wide and 
two feet deep. The extensive shoal or patch of reef that runs north 
from this island seems to be in much the same condition now as it 
was a century and a half ago, except that there appears to have 



STRUCTURE OF THE TURKS ISLANDS 267 



been a northward extension of a few hundred yards since that 
date. 

The original length of Greater Sand Cay is indicated by the shoal, 
from which some rocky points protrude a few feet above the sea, 
that stretches nearly two miles to the north of the island. Originally 
there was a long narrow island, quite three miles in length, of which 
the northern half has been swept away; whilst the southern was 
broken up into fragments that have since been joined together by 
the reclaiming agency of the waves. This process of reclamation 
will continue, and a low sandy tract will occupy the place of the 
shoal extending to the north ; while the island will add to its breadth 
on its western side. The process of preserving the remains of the 
original island is, however, not yet completed at the southern 
extremity, where the aeolian rocks form a steep promontory that is 
still exposed to the full force of the breakers in the open ocean. 

The opposing forces of destruction and reclamation are in opera- 
tion all over the Turks Group. Where the tendency to protective- 
beach formation is slight, as with Long Cay, we see a long strip of 
aeolian rock being broken into fragments by the waves. We see in 
Pear Cay and in Eastern Cay two islands that were once one, but 
are now separated by a rock- studded channel, half a mile in width, 
that has been the scene of more than one of the shipwrecks in this 
locality. Pear Cay seems likely to disappear altogether in the 
course of time. Eastern Cay, however, has since doubled its extent 
by the formation of a broad sandy tract on its west side ; and while 
the breakers are ever pounding away against the precipitous cliffs 
of aeolian sandstone on the eastern side, the waves are ever adding 
to its area on the west. 

The Composite Structure of the Larger Islands of the 
Turks Group. — In the larger islands the process is a little more 
complex. The extension of sandy flats from different " nuclei " of 
aeolian rock here led to the enclosure of mangrove-fringed lagoons, 
which are now in various stages of silting up and of being cut off from 
the sea. Thus the lower levels of these islands are sandy where 
they have been heaped up by the waves, and loamy where they 
have been reclaimed by the silting of the lagoon. 

We will begin with Grand Turk, an island about five and a half 
miles long and averaging rather over a mile in breadth. A ridge of 
aeolian sandstone runs along the eastern border of the island, attain- 
ing a height of seventy feet along much of its length, the greatest 
elevation being seventy-five feet. In addition there are low hills 
and rising ground of lesser elevation in the north-west, south-west, 
and centre of the island. But the greater portion of its surface is 
raised only a few feet above the sea, being no higher than the waves 
could have elevated it. Two large lagoons, the North and South 
Creeks, originally penetrated nearly to the centre of the island. 
Both were lined by a dense growth of mangroves, which are now 
almost entirely confined to the South Creek; and both occupied 
depressions that were below the sea-level. 

The ridge and lesser elevations of Grand Turk once formed islands 
of aeolian sandstone representing a large land-mass of the same 



268 PLANTS, SEEDS, AND CURRENTS 



formation that had been broken up by the waves. The growth of 
coral and the heaping up of reef debris led to the development of 
extensive sandy flats which reconnected the islands and enclosed the 
lagoons. The reclaiming agency of the mangroves regained large 
loamy tracts at the borders of the lagoons ; whilst the sandy tracts 
were ever increasing by accretion through the materials heaped up 
by the waves. One of these methods of reclamation is well displayed 
at the southern end of the island, which, according to the residents, 
has extended considerably in recent years through the formation of 
successive lines of sandbanks. It is strange that the significance of 
the great recovery of land from the sea that is involved in the 
building-up of Grand Turk did not present itself to A. Agassiz, 
since he states that whilst the eastern border of the island is formed 
by " a narrow ridge of seolian hills," the breadth of the island in its 
centre consists of " flats " formed by the recent growth of shore 
coral-rock Indeed, everything that is of importance to man on 
Grand Turk, and particularly its salt-pan industry, is due to the fact 
that it has been largely reclaimed from the sea. 

A word may be said about the two lagoons of Grand Turk. The 
South Creek was doubtless originally far more patent than it is at 
present. It is covered during the higher part of the tide; but at 
low-water it is exposed, and extensive mud-flats monopolise its 
area. Salt-rakers have been busy here for over two centuries, and 
have evidently largely transformed this part of the interior of the 
island. It is likely that the " salinas " or salt-ponds represent the 
original extension of the South Creek into the centre of the length 
of Grand Turk. The North Creek is a clear sheet of water about 
one and three-quarter miles long and 600 to 700 yards broad. It is 
credited with a depth of four fathoms in the Admiralty chart, and 
is now nearly silted up at its mouth. These matters are also referred 
to in the remarks on the topography of the island in Chapter XII. 
The delineation of the two creeks in the Admiralty chart (No. 1441), 
which dates back to 1830 and 1845, is puzzling. The details of the 
interior of the island are given in a large-scale map (three inches to 
a mile) based on a survey executed in 1902-4 by J. F. Osborn (Colonial 
Surveyor) and on the Admiralty chart just mentioned. The depths 
of the sea around, that are given in this map, are merely taken from 
the soundings in the chart. 

Salt Cay reproduces all the features of Grand Turk, and it has had 
the same history Though about three miles in length and about 
one and a half miles in breadth, its surface is for the most part 
elevated only a few feet above the sea, the low ridges and hummocks 
of seolian sandstone, that rise in places to heights of sixty feet, having 
served as " nuclei " for the growth of extensive low flats of coral and 
reef debris. Here also there were lagoons communicating with the 
sea, their shores lined by mangroves that have been almost entirely 
cleared by the labours of the salt-rakers, who, in making their 
" salinas," have transformed the interior of the island. Apart from 
the salt-ponds and the shallow ponds scattered about, a large creek, 
still communicating with the sea on the south-east coast and bor- 
dered in 1911 in one or two places by mangroves, recalls the original 



STRUCTURE OF THE TURKS ISLANDS 269 



condition of the island when large lagoons occupied its interior. 
Whilst a region of sand-dunes lies behind the beach at the north end 
of the island, illustrating the constructive action of the waves and 
of the winds, extensive bare rocky surfaces in the interior represent 
the work of the coral reef. The same features are presented by 
Cotton Cay. Here again islets of seolian sandstone, now existing as 
elevations, thirty to forty feet high, at its two extremities, have 
been joined by the reclaiming agencies of the waves and of coral- 
reef growth ; but the lagoons have long since been cut off from the 
sea, and are now represented by shallow ponds in the centre of the 
island. 

No Recent Change of Level in the Turks Islands. — Of 
changes in level, whether of elevation or of subsidence, I found no 
evidence in this region. No old erosion lines came under my notice, 
except in one or two places where it was apparent that they had 
been merely cut off from the sea by the intervention of a beach or of 
a reef-flat. That the level of the sea has remained much the same 
for a long period is indicated by the circumstance that the platform 
of reef-rock and ordinary beach-sandstone, on which the seolian 
sandstone reposes, has been formed with the sea at its existing 
level. 

Probable Destruction in Great Part of the Original 
Islands of the Turks Group. — There must have been great 
destruction of the original islands of seolian sandstone before the 
modern process of reclamation was made possible by the shoaling 
of the great bank from which the present islands rise. The low hills 
and ridges of the larger islands and the small rocky cays are but the 
scanty remains of what may have been two or three large islands of 
seolian rock that occupied almost all the bank. At a uniform depth 
of nine or ten fathoms the bank extends seven or eight miles eastward 
of Eastern and Pear Cays, and then plunges down into the depths. 
All this submerged area was once covered by land of seolian forma- 
tion. The same may be said of the two long tongues that extend 
north and south from the opposite extremities of the group at a 
depth of about ten fathoms for about seven miles in each case. The 
same is also true of the inter-island tracts of shallower water. All 
this land has disappeared. 

The same has been inferred by A. Agassiz for the whole 
Bahamian Region. — All the questions raised by the consideration 
of the Turks Islands are issues raised in connection with the seolian 
rocks of the Bahamas as a whole. The original much greater extent 
of the land-surface of seolian rocks, which has been postulated by 
me in the case of the Turks Islands, was assumed twenty years ago 
by A. Agassiz for the whole of the Bahamian archipelago. Before 
the last subsidence of 300 feet, which, as he infers, affected the whole 
region (a point on which the present writer, as already shown, is not 
in agreement with him), the present banks were occupied, as he 
holds, by " one huge irregularly shaped mass of low land." How- 
ever, as I have pointed out, several of the eastern banks are now 
separated by passages 1000 to 2000 fathoms deep. We cannot, 
therefore, postulate for that period a continuous land- surface over 



270 PLANTS, SEEDS, AND CURRENTS 



the area occupied by the present archipelago ; but, judging from the 
size of the larger banks, several of the islands must have been as 
large as an ordinary English county. In addition to the original 
islands of seolian formation, of which fragments still remain, there 
were several others, of which no trace now remains beyond the 
submerged bank that has been generally worn down to the lower 
limit of breaker-action, except where it displays a few " rocks awash." 
Probably none of the islands exceeded 500 feet in elevation, and 
their average height must have been less than half this amount. 
Their entire surfaces were covered by wind-blown sand; and, in 
fact, their entire thickness was the work of the drifting dune. The 
compacted aeolian formations, of which they are now composed from 
top to bottom, plainly tell the story of the building up of these 
islands; and there is little to indicate that there was any covering 
of vegetation of any extent. 

The History of the Bahamas is the History or the Sand- 
dune. — These large islands were built up under the sway of the 
shifting sand-dune, and must have offered a spectacle not to be 
found on the same scale in any insular territory in the present era, 
not even in the great coral-reef regions of the Indian and Pacific 
Oceans. These unusual formations, unusual in the sense just 
defined, required unusual conditions; and we have now to ask 
ourselves what exceptional conditions offered the opportunity for 
the dominion of the dune. 

They must have been the conditions that prevail on the sea-board 
of those great continental masses where the dune holds its sway. 
At the present time the most insignificant sandbank in coral seas 
becomes the home of the mangrove, and numerous other plants 
establish themselves as the bank emerges from the waves. We do 
not read in our own day of islands in coral seas that are swept clean 
by ever- shifting sand-dunes. The Turks Islands lie in a region of 
storms and gales ; and if ever strong winds could restore the original 
sterility of these islands we might look for their work here. Yet, 
what do we find ? In an island like Salt Cay, where the sand-dunes 
are well developed in places, they make but little effort to overrun 
the surface. The conditions of the present are confessedly not 
those of the past ; and in what, we may ask, has been the change ? 

Before answering this question, let us picture to ourselves the con- 
ditions that once prevailed over insular land- areas, fifty to a hundred 
miles across, where the drifting sands reigned supreme, conditions 
that, as above remarked, are now only found on the sea-board of 
great continents. The coast regions of Peru are the home of the 
shifting sand-hill, or " medano," so graphically described by Dr. von 
Tschudi in his Travels in Peru (London, 1847, p. 243). A fine light 
yellow drift-sand here covers hill and dale, and when driven by 
violent winds the medanos pass rapidly over the sandy plains. The 
smaller ones, though moving quickly forward before the larger ones, 
are soon overtaken and overwhelmed by them. At one time they 
cover the plain. At another they move across its breadth in rows. 
The whole face of the landscape may in this manner be transformed 
in a few days, and the traveller who had previously lost his way 



STRUCTURE OF THE TURKS ISLANDS 271 



amidst a labyrinth of sand-hills may on his return traverse a clean- 
swept plain where not a single medano obstructs his view. Though 
the sand is not formed of calcareous materials, but is derived from 
the disintegration of andesitic rocks, the lesson will be the same. 

In February 1904 I spent several days in examining the medanos 
of the Ancon coast-region north of Callao. Since the details are 
given in Note 34 of the Appendix, I will confine myself here to a 
few general remarks. Sand covers the broad plains and the lower 
hill-slopes and completely hides the crests of hill-spurs, 400 feet in 
height, as they descend to the coast. At the time of my visit these 
crescentic mounds, usually six to ten feet high and twenty-five to 
thirty feet across, formed a line, or rather a column, of two or three 
irregularly abreast traversing a sandy waste of hill and plain for a 
distance of from four to five miles, and crossing ridges and spurs 
300 or 400 feet in height. I watched them as they came into being 
near the beach and as they died away miles inland a few hundred 
feet up the slopes of the main range in their fruitless endeavour to 
scale the mountains. I spent hours in watching them dribbling 
over the sharp crest of a mountain-spur that descends to the coast 
immediately south of Ancon. They had reached the crest after a 
climb of about 350 feet from the beach below, and as I sat on the 
ridge-top observing them, they peppered my face with their finer 
6and with each fresh gust of wind. The sand usually formed a con- 
tinuous slide during the descent of the steeper northern slopes of 
the ridge, the medanos shaping again when the sand reached the 
plain ; but where there was a gentler gradient they re-formed half- 
way down the slopes. During my sojourn the prevailing winds were 
light, and, as measured by me, the medanos moved forward only a 
few inches a day ; but before a fresh wind they would advance yards 
daily. Before a gale they would move rapidly across the plains, and 
a strong wind blowing athwart their line of advance would in the 
course of a day or two level them with the ground. Von Tschudi 
also describes medanos with immovable bases formed around blocks 
of rocks that are scattered about the plain. While the sand is heaped 
up by the wind on one side,~~it descends on the other; and there is 
nothing permanent about this type of medano but its site and its 
conical shape. The moving medano, however, is the great distributor 
of sand over the arid wastes of the sea-board of Peru. Sterility 
reigned over the sand-covered plains and hill-slopes of Ancon. Only 
occasionally one came upon patches of a little bromeliaceous 
"tumble-weed" (Tillandsia), which, however, became more frequent 
as the plains approached the foot of the mountains. 

But, to return to the large islands of the Bahamas, as they origin- 
ally were, covered with and built up by drifting sand, with little or 
no vegetation to compete with the dominion of the sand-dune, the 
conditions of the present are confessedly not those of the past, and 
in what, we may again ask, has been the change ? I would suggest 
with some diffidence that the climatic regime which now prevails 
on the sea-borders of North Chile and Peru once existed in the 
Bahamian region. Just as the cold waters of the Humboldt or 
Peruvian Current determine the relative sterility of that continental 



272 PLANTS, SEEDS, AND CURRENTS 



sea-border by causing the precipitation of the moisture carried by 
the prevalent south-west winds before they reach the land, so in 
the past a cold current from the north swept along the northern 
shores of the Bahamas and cut off the moisture carried by the north- 
east trade-winds. From tljis point of view the seolian formation of 
the Bahamas represents the New World's response in ancient times 
to the influences producing arid sea-borders in warm latitudes (cold 
currents and drying winds), but in a region of calcareous sands and 
under insular conditions, an association of circumstances not repeated 
on the same scale in any other part of the globe. 

At present, as Commander Campbell Hepworth informs me, the 
influence of the Labrador or Arctic Current as a surface- stream may 
be traced along the shores of the United States as far as the Florida 
Straits during most of the year. But how little do we know of the 
arrangement of the surface-currents in earlier times ; and what, we 
may also ask, would be the behaviour of the Arctic Current if 
the great Equatorial Current, from which the Gulf Stream takes its 
rise, flowed in mass, as it probably once did, across the site of the 
present Panama Isthmus into the Pacific? The effect of the 
emergence of this isthmus was the birth of the Gulf Stream, and the 
effect of the Gulf Stream was the dissipation to a large extent in 
tropical latitudes of the cold current from the north, so that the 
Bahamian region would no longer come under its influence. Before 
the change we had here the same association of aridity with a cold 
current that exists on the sea-border of Peru and also on the sea- 
borders of South California and North Mexico, where the moisture- 
laden winds, by passing over the cool waters of the Californian 
Current, become drying winds when striking the continent and 
produce the aridity of its sea-border. In the cases of the South 
African Current and the west coast of South Africa and of the West 
Australian Current and Western Australia we seem to have the 
same association of conditions. [For further particulars of the 
writer's views on the influence of the Humboldt Current on the 
climate of the Pacific border of South America reference should be 
made to pp. 490-6 and 500 of his work on Plant Dispersal (1905)]. 

I may add that the association of the birth of the Gulf Stream 
with the elevation of the Panama Isthmus is by no means a new 
idea. The various rearrangements of the land-areas in the tropics 
of the New World adopted by some botanists, zoologists and geolo- 
gists often involve the shutting off of the Gulf Stream from the 
North Atlantic. However much Darwin's great authority may have 
weighted the scale against them, the " extensionists " have obtained 
results in these tropical regions that call for a re- valuation of their 
testimony. 

The Standpoint of the Extensionists. — Reference may again 
be made to the relations between the western Bahamas and 
the adjacent islands of the Greater Antilles. Though depths of 2000 
fathoms divide the eastern Bahamas from Hispaniola, much shallower 
submarine connections exist between the Great Bahama Bank and 
Cuba, and the possibility of a Cuban land-connection in times that 
are past cannot be ignored. This leads one to refer to an alternative 



STRUCTURE OF THE TURKS ISLANDS 273 



explanation of " things Bahamian," which, although based mainly on 
zoological evidence, makes a serious claim on some of the geological 
testimony that the " anti-extensionist " is wont to regard as peculiarly 
his own. 

The remarkable similarity in geological structure between the 
Bermudas and the Bahamas is rightly emphasised by Scharff in his 
Distribution and Origin of Life in America (1911, p. 185) ; and he is 
justified in doing so, since the peculiar geolian formation of these two 
regions cannot be matched on the same scale in any insular region of 
the globe. Should the same formation exist in Florida, the point 
would acquire yet more importance. Laying stress on the zoological 
argument that we are not concerned here with land- areas stocked 
with " waifs and strays," but with ancient land-surfaces possessing 
faunas often peculiar in their character, he advocates the hypothesis 
that in Tertiary times the Bahamas and the Bermudas were included 
in a land- area that joined together the Greater Antilles and was 
connected with Florida (p. 186, and maps facing pp. 280, 294). 

He points out (pp. 288-9) that although displaying affinities with 
neighbouring regions, the Bahamas possess reptilian, amphibian and 
molluscan faunas that are often largely their own. In this connection 
Dr. Scharff could have also summoned to his aid the witness of the 
plants. In the tropical Pacific, low islands, like those of the Bahamas, 
would have been stocked through the agencies of birds and currents 
with cosmopolitan and wide-ranging plants, and would have dis- 
played little or no endemic element. On the other hand, the plants 
of the Bahamas, as shown in Chapter XII., exhibit a marked Bahamian 
impress ; and present characters that could only have been developed 
during ages of isolation from other regions. 

Note added August 2, 1916. — It will be shown in one of the last 
notes of the Appendix that according to Dr. Vaughan and other 
American geologists the similarity in geological structure between 
the Bermudas and the Bahamas extends to the seolian origin and 
calcareous character of the deposits, but not to their mechanical 
condition. A reply will there be made to the query concerning the 
occurrence of this formation in Florida. 

Summary 

1. The low islands of the Turks Group, which belong geographic- 
ally and botanically to the Bahamas, possess the geological features 
so characteristic of that archipelago. They are composed in their 
higher parts of seolian sandstone, which is made of consolidated 
calcareous drift-sand, and in their lower parts of coral-reef debris 
thrown up under the existing conditions of sea-level. They possess 
all the other general characters of the Bahamian Islands, which are 
situated on banks that at the eastern extremity of the archipelago 
rise from the ocean's depths and at the western end have shallower 
connections with the North American continent and the island of 
Cuba. 

2. It is pointed out that only in coral-reef regions could we look 
for the conditions that have produced a great archipelago with such 

T 



274 PLANTS, SEEDS, AND CURRENTS 



uniformity in characters as found in the Bahamas; and it is urged 
that the coral atoll makes a peremptory demand to be called as a 
witness in this connection. It is suggested that the Bahamas were 
in ages past the Laccadives and Maldives of the Atlantic. The 
implication is that atolls originally crowned the summits of the 
ranges of submarine mountains that are now represented by the 
banks of the Bahamian seas, atolls long since overwhelmed by the 
shifting sand-dune, the work of which is presented in the seolian 
sandstone of our own day. But, as in the linear grouping of atolls, 
formed by the Laccadive and Maldive archipelagos, there is a " con- 
tinental " end, where the Bahamian archipelago abuts on the adjacent 
continent, and an " oceanic " end, where it projects into the ocean's 
depths; and it is hinted that the standpoint adopted concerning 
Bahamian problems largely depends on whether the investigator 
was familiar with the continental or the oceanic portion (pp. 255-6). 

3. Then follows a discussion of the views of Alexander Agassiz 
on the formation of the Bahamas. The present writer's detailed 
examination of the Turks Islands, during a sojourn of three months 
in the group, enables him to approach the problems from the 
"oceanic" standpoint; but, although at one with the eminent 
American investigator as regards the leading structural features of 
the group, he ventures to differ from him on some points of inter- 
pretation. Thus, there can be little doubt that the existing Bahamas 
are the remains of great tracts of low land of seolian formation that 
have been in great part destroyed by the waves; but the writer 
holds that the degradation occurred under the present conditions of 
sea-level, and not during a subsidence of 300 feet as is assumed by 
Agassiz. Then, again, the writer emphasises the great work of the 
reclaiming agencies under present conditions, a matter on which 
Agassiz lays little stress. Amongst other incidental points of differ- 
ence are objections that he does not attach sufficient importance to 
the isolation of the eastern islands by the ocean's depths, and that 
the foundations of the seolian formation lie near the existing sea- 
level, and not far beneath the waves as is implied by his subsidence 
hypothesis (pp. 256-9). 

4. The author then gives the results of his observations on the 
Turks Islands. The formation of the seolian sandstone is first 
discussed, and the absence of marine remains is pointed out. In 
this connection the results obtained by Louis Agassiz on the Salt 
Key Bank are utilised. It is remarked that if Nature busied herself 
ages since in producing the seolian rocks, she is now actively engaged 
in their destruction. Yet there is a process of reclamation at work 
that will ultimately prevail, and new land has been, and is being, 
formed around the remnants of the early islands. Disconnected 
islets of seolian rock, that are the fragments of a large island, have 
been, and are being, joined together again into one island by the 
growth of coral reefs and the formation of sandbanks. In this 
manner the destructive action of the waves has often been stayed ; 
and in the larger islands, while the more elevated " nuclei " of seolian 
sandstone belong to the past, the low tracts of land that have been 
formed around them belong to the present (pp. 259-262). 



STRUCTURE OF THE TURKS ISLANDS 275 



5. The question of the foundations of the aeolian rock is then 
dealt with, and the reply is that in the Turks Islands the aeolian 
sandstone passes down into consolidated reef debris, consisting of 
coarse sand, dead shells, and coral fragments, which have been 
thrown up on reef rock under the existing conditions of sea-level 
(pp. 262-4). . 

6. Whilst discussing the modern process of reclamation m the 
Turks Group, the structure of the islands is treated in detail ; and it 
is shown that in the case of the larger islands, where lagoons have 
been usually enclosed during the development of the new land, the 
mangroves have been an important reclaiming agency (pp. 265-9). 

7. The comparison of old and recent charts of the Turks Islands, 
and of the Bahamas generally, does not often yield definite results ; 
but we may quote the conclusion of Alexander Agassiz, who paid 
considerable attention to the matter, that the configuration of the 
Bahamas has not been materially changed since their discovery by 
Columbus, a conclusion that involves the implication that during a 
period of 400 years no great change has occurred in the relations 
between land and sea in this region (pp. 264-5). 

8. All the questions raised by the consideration of the Turks 
Islands are issues raised in connection with the Bahamas as a whole. 
The original much greater extent of the land of aeolian origin, which 
is postulated by the author in the case of the Turks Islands, was 
assumed twenty years ago by A. Agassiz for the whole Bahamian 
region. Although we cannot assume that in distant ages a con- 
tinuous land-surface occupied the area of the existing archipelago, 
it is probable that several of the islands were as large as an average 
English county and that their maximum elevation did not exceed 
500 feet. They were completely covered by wind-blown sand, and 
in fact their entire thickness was the work of the drifting dune, 
there being little to indicate that there was any covering of vegetation 
of any extent (pp. 269-270). 

9. The history of the Bahamas is the history of the sand-dune. 
The original islands must have offered a spectacle not to be found 
on the same scale in any insular territory in the present era, not 
even in the great coral-reef regions of the Indian and Pacific Oceans. 
These unusual formations require unusual conditions, and the author 
looks for them in the conditions that prevail on the sea-board of a 
great continent where the dune holds its sway. The conditions of the 
present in the Bahamian region are confessedly not those of the past ; 
and in what, we may ask, has been the change (pp. 270-1) ? 

10. Before answering this question, the author describes the sand- 
wastes on the sea-board of Peru, where the shifting sand-hill reigns 
supreme, and here he draws in part on his own experiences. He then 
replies to the query above put, and suggests that just as the cold 
waters of the Peruvian Current determine the aridity of the sea- 
boards of North Chile and Peru, so in ancient times a southward 
extension of the Arctic or Labrador Current would have produced 
similar effects on the Bahamas (pp. 271-2). 

11. Not to be ignored, however, is the view of the " extensionist " 
school based on zoological evidence that the Bahamas and the 



276 PLANTS, SEEDS, AND CURRENTS 



Bermudas were in later Tertiary times included in a land-area that 
extended to Florida and united the Greater Antilles. It indicates 
that the last word has not been said in this matter (pp. 272-3). 

12. Some conclusions arising from the recent work of American 
geologists in the western Bahamas with additional remarks on the 
question of the " ocean-holes " will be found in one of the last notes 
of the Appendix. 

LIST OF SOME OF THE WORKS QUOTED IN THIS CHAPTER 

Agassiz, A., A Reconnaissance of the Bahamas, Bull. 31 us. Comp. Zool. : Harvard, 
Vol. XXVI., 1894. 

Agassiz, L., The Bahamas and Salt Key Bank, Bull. Mus. Comp. Zool., Vol. I. 
Quoted at length by Dana in the work below named. 

Dana, J. D., Corals and Coral Islands, 1872. 

Tillinghast, W. H., Notes on the Historical Hydrography of the Handkerchief 
Shoal (Mouchoir Carre) in the Bahamas, Library of Harvard University, Biblio- 
graphical Contributions, No. 14, 1881. 

Vaughan, T. W., Geological Investigations in South Florida and the Bahamas, Tear 
Book of the Carnegie Institution of Washington, Nos. 13 and 14, 1914, 1915. 

W atkins, F. H., Turks and Caicos Islands, Report on the Salt Industry, Colonial 
Reports — Miscellaneous, No. 56, 1908. 

Old Chart of Turks Islands, from a survey made in 1753 by the sloops UAigle 
and U Emeraude, by order of the French Governor of Hispaniola, with improve- 
ments from observations made in 1770 in the Sir Edward Hawke, King's 
Schooner : Laurie and Whittle, 53, Fleet Street, London, 1794. 



CHAPTER XII 



THE FLORA OF THE TURKS ISLANDS 

We come now to an account of the flora of the Turks Islands. 
The vegetation is generally sparse and may be described as " scrub," 
the soil being sandy and loamy and containing usually but little 
humus. Different " cultivations " have been from time to time 
carried on in the larger cays, especially on Grand Turk. But the 
cultivated plants are few that will thrive in a sandy and often saline 
soil, and, except for the clearances of the mangroves bordering the 
lagoons and creeks in the construction of salt-pans, the botanist 
will not find great difficulty in restoring much of the indigenous 
flora of the large inhabited islands. In this he will be assisted by 
the examination of the smaller uninhabited cays, and it is to these 
smaller islands that my remarks will at first apply. Though goats 
have been allowed to run wild on most of them at one time and another, 
this practice had been largely discontinued at the time of my visit 
in 1911. Their presence might account for small-seeded weeds like 
Portulaca oleracea, etc., and might explain to some extent the scarcity 
of fleshy beach plants like Sccevola plumieri on the lesser cays; 
but otherwise I should not imagine that through their agency the 
original features of the flora, as presented in the smaller islands, 
have been much obscured. 

In an extract from the Annual Register of 1764 given by Com- 
missioner Watkins in his report on the history of the salt industry 
of these islands, we read that they are " sandy and barren with very 
little, if any, fresh-water, without any vegetables except low shrubs, 
or any animals except lizards, guanas, and land-crabs." Though 
this reference was made more than a century after the Bermudian 
salt-rakers began to visit the group, it was not until about 1678 that 
they commenced systematic salt-raking during their annual sojourns 
from March to November. It is a testimony to the obdurate nature 
of the soil and to the difficulty of Nature's task in stocking these 
islands with plants that so little has been effected since they were 
first occupied by Europeans. Of course, in the larger inhabited 
islands of Grand Turk and Salt Cay man has done something to 
alleviate these conditions. But still their soil is not fit for raising 
much else than sweet potatoes, guinea corn, and plants that thrive 
in poor ground. For their fruits and vegetables the Turks Islanders 
are almost entirely dependent on outside supplies. Yet, notwith- 
standing the provision of government-ponds and tanks to hold the 
rain-water, great inconvenience is often experienced during the dry 

277 



278 PLANTS, SEEDS, AND CURRENTS 



hot season. In the not infrequent droughts cattle die in numbers, 
and the gardens of the inhabitants lose most of their plants. 

My principal object being to study the process of stocking the 
small islands of these seas with plants, I was content to largely 
limit my observations to such an inquiry. But it was also necessary 
to obtain some acquaintance with the more extensive flora of the 
largest island (Grand Turk) ; and though there are gaps in my 
knowledge of its plants my remarks will, I trust, enable the reader 
to form some idea of the peculiarities of its flora and of the general 
facies of the vegetation. Dr. Millspaugh, who studied the plants 
of this group with the eye of a systematist of great experience in 
these regions, will be able to give a far more authoritative and com- 
plete account. I looked at matters not with the discriminative 
eye of the systematist, but from the standpoint of dispersal. This 
position was rendered comparatively easy in the case of the plants 
of the smaller cays, since they were largely stocked with wide- 
spread strand plants that had long been familiar to me in tropical 
regions. 

The flora of the smaller cays is, as I have just said, chiefly a strand 
flora. Characteristic West Indian littoral plants have often taken 
charge of these small islands. In my description I will begin with 
the smallest uninhabited cays that are formed almost exclusively 
of seolian sandstone with but little beach or fore-shore. Next I 
will take those larger in size, where low-lying, littoral tracts have been 
added to the nucleus of aeolian rocks, and will then pass on to the 
large inhabited islands where man has exercised a greater disturbing 
influence. 

Pear Cay, which derived its name from the abundance of Prickly 
Pear, is, according to the chart, about forty feet high and about 
600 yards long. It is entirely formed of seolian rock; and, since it 
possesses scarcely any beach, landing is not practicable when the 
sea is rough. Much of the lower levels are strewn with sand supplied 
by the disintegration of the sandstone, and here flourish Tournefortia 
gnaphalodes, Suriana maritima, Ipomcea pes-caprw, Sesuvium portu- 
lacastrum, and Corchorus hirsutus with a little Heliotropium curas- 
savicum. I have referred in Note 3 of the Appendix to the manner 
in which the species of Tournefortia, Suriana, and Corchorus adapt 
themselves to the wind-pressure in this wind-swept cay, and I need 
not particularise it here. On the upper portion there is little or 
no sand and the rocky ground is almost exclusively occupied by 
Ipomoea tuba, which largely conceals the broken slabs of sandstone 
that lie about. In addition there was a Cyperus (C. brunneusl), 
which is common on all the small cays. 

The Cactuses of the genus Opuntia, that occur here and on most 
of the small cays and larger islands, are not differentiated in my 
description. They form a feature of all the islands, and include 
two common species, Opuntia tuna, the Prickly Pear, which is the 
most frequent, and another with very long spines, locally known 
as " Dildo," perhaps 0. triacantha, Haw. 

Penniston Cay is a long flat strip of aeolian sandstone, twenty- 
five or thirty feet high. According to the Admiralty chart it would 



THE FLORA OF THE TURKS ISLANDS 279 



be about 800 yards long and a cable (200 yards) broad; but these 
dimensions appear to me rather excessive. Its surface, which is 
largely of bare rock, much honeycombed in some places and slabby 
in others, is scantily vegetated. Having no beach worth mentioning 
it receives the full brunt of the breakers, which have forced a passage 
near its southern end where there is a natural arch. In rough 
weather the seas deposit drift in the middle of its breadth. The 
principal plants growing on it were Tournefortia gnaphalodes, Borri- 
chia arborescens, Suriana maritima, Portulaca oleracea, Sesuvium 
(two species), and a little Euphorbia buxifolia. On the lee side in 
its southern portion there was a large patch of Opuntia, where Frigate- 
birds were nesting in numbers. 

Long Cay, like Penniston Cay, is a long and narrow flat strip of 
seolian sandstone, raised twenty-five or thirty feet above the sea 
and possessing one or two small beaches. It, however, receives the 
full force of the breakers on its north-eastern side, and portions of 
the original island now form islets at its extremities. As delineated 
in the Admiralty chart its length would be about a mile and its 
maximum breadth about 400 yards. However, I paced its width 
in the broadest portion and did not make it much over 120 yards. 
The surface is mainly of bare rock, covered, however, with sand 
thinly in places. 

Though much of its area had no covering of vegetation there 
were considerable portions occupied by plants, especially on the lee 
or south-western side, where there were extensive thickets, four 
to six feet high, of the Seven-year Apple (Genipa clusiifolia), both in 
fruit and in flower, mingled in places at the seaward margin with 
Coccoloba uvifera. Next in frequency, growing semi-prostrate, 
or clambering over the rocks, was a variety of Conocarpus erectus. 
This is probably the form " procumbens " of Jacquin; but its 
occurrence is chiefly limited to the weather or eastern extremity 
of the island, to which the epithet " wind-swept " fitly applies ; and 
doubtless it is a station variety. Millspaugh found this form in the 
Bermudas and on the coasts of Yucatan, and describes it in his 
Plantce Utowance (Field Columb. Mus. publ.). Borrichia arborescens 
should also be reckoned as one of the most frequent of the plants 
on this cay. Most of the common beach plants of these islands are 
here represented, sometimes on the rocky portions, sometimes on 
the sandy parts, such as Tournefortia gnaphalodes, Suriana maritima, 
Ipomoea pes-caprce, Euphorbia buxifolia, Sesuvium portulacastrum, 
etc. But Sco3vola plumieri, which never came under my notice 
on these small wind-swept cays, was not observed. Where a thin 
covering of sand lies on the rock, the surface is almost carpeted with 
Ambrosia erithmifolia associated with Cyperus brunneus. Near the 
north-west end of the island Rhachicallis rupestris forms an extensive 
patch of scrub one and a half to two feet in height. We learn from 
Dr. Millspaugh (Prcenunc. Baham.) that this plant grows on maritime 
rocks throughout the Bahamas and is " often the only vegetation 
on many of the sea-washed islets." 

We now pass from our description of the small rocky cays of seolian 
sandstone possessing but little beach, and swept over a large portion 



280 PLANTS, SEEDS, AND CURRENTS 



of their surfaces by the sea in stormy weather, to the other small 
uninhabited cays where the waves have thrown up more or less 
extensive tracts of low-lying land fronted by beaches around a nucleus 
of seolian sandstone. Here the strand plants that mainly stock these 
small cays find congenial conditions on the sandy tracts behind the 
beaches as well as on the seolian rocks of the higher levels. The 
cays concerned include Eastern Cay, Greater Sand Cay, and Gibb 
Cay, with Round Cay adjacent to it. Both as regards the stage in the 
history of island formation and as concerns the conditions for plant 
growth, they present an intermediate state between the small rocky 
cays above described and the large inhabited islands to be sub- 
sequently noticed. Here, as in Eastern Cay, the Turk's-head Cactus 
(Melocactus communis), first appears, which is, or was, more at home 
in the large islands. Here also, as in Gibb Cay, are found plants, 
like the Burnt-bush (Euphorbia vaginulata) and Phyllanthus, that 
abound on the large cays, as on Grand Turk. 

Eastern Cay, as delineated in the chart, is about 1800 yards 
long and has a maximum breadth of nearly 800 yards. On its north- 
west side there is a broad sandy plain elevated a few feet above the 
sea and running back between 400 and 500 yards to a stony ridge, 
which attains an elevation of ninety-six feet and forms the backbone 
of the island. Near the ridge the sandy plain gradually rises until 
it reaches half-way up its slopes. Characteristic littoral plants 
such as Tournefortia gnaphalodes, Euphorbia buxifolia, Ipomoza 
pes-capras, Sesuvium portulacastrum, Portulaca oleracea, and Borrichia 
arborescens grow at the border of the sandy beaches and on the ground 
in their rear on both sides of the island. Apart from the plants 
growing on the beaches the three most conspicuous features of the 
vegetation of the island are (1) the abundance of Ambrosia crithmifolia 
which covers the sandy plains and the lower sandy slopes on both 
sides of the island with a dense carpet, (2) the frequency of Borrichia 
arborescens which mainly occupies the upper stony slopes, (3) the 
prevalence of the Turk's-head Cactus (Melocactus communis), which, 
though growing on the lower sandy slopes is most abundant in the 
higher part of the island. 

Corchorus hirsutus is also common on the lower levels, growing 
semi-prostrate on the sandy plains and associated in places with 
Sesuvium. I noticed two or three fair-sized colonies of Ipomcea 
tuba on the stony ground fifty or sixty feet above the sea. Cactuses 
of the Opuntia type are common in the island, especially at and near 
the summit. During my two visits I failed to find either Suriana 
maritima or Genipa clusiifolia or Sccevola plumieri. 

Gibb Cay, which is about 700 yards long, 200 yards broad, and 
about sixty feet high, is almost surrounded by beaches, and has sand 
strewn nearly all over its surface. Much of this sand is evidently 
derived from the disintegration of the seolian sandstone which is more 
friable than usual. The beach plants, which include Tournefortia 
gnaphalodes, Sccevola plumieri, Suriana maritima, Conocarpus erectus, 
Euphorbia buxifolia, Sesuvium portulacastrum, Ipomcea pes-caprm, 
and the tall reed-grass, Uniola paniculata, extend with the usual 
exception of the first named some distance up the slopes and reach 



THE FLORA OF THE TURKS ISLANDS 281 



often the higher levels. Leaving the beach behind we find Ipomosa 
tuba growing nearly all over the undulating sandy summit, but 
with numerous associates, sometimes Ipomcea pes-caprce, Ambrosia 
crithmifolia and Sesuvium, at other times Phyllanthus epiphyllanthus> 
Euphorbia vaginulata, and Borrichia arborescens. The steep sandy 
slopes are preferred by Sccevola plumieri. The Cyperus of the other 
smaller cays also occurs, and I noticed an amarantaceous herb by 
the beach. Goats and other animals have often been kept on this 
island, and no doubt have affected the relative prevalence of the 
different plants. 

Round Cay is an islet lying about two cables or 400 yards from 
Gibb Cay, of which it doubtless originalfy formed a part. It is 
composed of the same friable seolian sandstone, the disintegration 
of which has supplied the sand that covers its surface. Its length 
is about 150 yards or so, and its height forty-five or fifty feet. On 
its flat summit thrive Tournefortia gnaphalodes, Sesuvium portulacas- 
trum, and Euphorbia vaginulata, with a little Euphorbia buxifolia 
and Portulaca oleracea. Cyperaceai and grasses are common. 

Greater Sand Cay, the most isolated island of the Turks Group, 
is of especial interest to the student of the dispersal of plants in this 
region. In sailing amongst the other islands one is in more or less 
protected waters, but to accomplish the six and a half miles that 
separate this island from Salt Cay the open ocean has to be traversed. 
As a result one may have to wait for days and weeks before suitable 
weather presents itself for reaching it, and on arrival it is not always 
easy to land, whilst there is always a risk of being detained there 
for some days by bad weather. The author spent two days on the 
island. Dr. Millspaugh, who visited it a few weeks afterwards, 
had difficulty in landing, the boat being turned over on top of him. 
It would seem that we were amongst the first to investigate its 
flora. This island is the first to catch the drift from the large West 
Indian islands to the southward and eastward, and quantities of 
seeds and fruits are stranded on the beach on its eastern side. Isolated 
as it is, the disturbing influence of man and animals cannot be excluded. 
Fishing-parties make a sojourn of a week or two, once or twice 
during most summers. The small sailing craft of these seas anchor 
occasionally on its west side to procure firewood, etc. Goats, again, 
have been kept on the island, one or two being still there when I 
visited it in March 1911. 

The island is about one and a half miles long, 500 or 600 yards in 
maximum breadth, and forty or fifty feet high. It is principally 
made up of two main masses of seolian sandstone, connected by a 
low neck of sand raised ten to fifteen feet above the usual high- 
water level, but breached by the sea during the hurricanes. Each 
of these principal portions is again subdivided, the two parts being 
connected by a low sandy neck which is also breached in stormy 
weather. During hurricanes the three necks are washed clean by 
the breakers and largely stripped of their plants. At such times the 
four nuclei of seolian sandstone are isolated by the waves. Greater 
Sand Cay is in truth one of the most wind-swept and sea- swept 
islands of these regions, and it is exposed to the whole force of 



282 PLANTS, SEEDS, AND CURRENTS 



the breakers of the open ocean. Plants with difficulty establish 
themselves on the beaches and on the necks, being liable to be swept 
away in the storms. When they take refuge on the more elevated 
portions of the island they are exposed to the violence of the hurri- 
canes. Numbers of dead prostrated trunks of Suriana maritima 
lay on the surface over the island during my visit, the victims mainly 
of the last hurricane two or three years before. 

Yet, with the exception of the low connecting sandy tracts, where 
plant growth is scanty or almost absent, the surface is fairly well 
vegetated. Owing mainly to the extensive disintegration of the 
aeolian sandstone the surface of the more elevated portions is largely 
covered with sand which is not less than seven or eight feet in depth 
in places, and thus affords a good burrowing ground for the large 
iguanas which abound. But the vegetation is what is termed of 
the scrub kind. If we were to give a brief description of the plant- 
arrangement we should say that the sandy soil is carpeted with 
Ambrosia criihmifolia, Cyperi, and coarse creeping grasses (Cenchrus 
echinatus, etc.), whilst clumps of Suriana maritima and thickets of 
Genipa clusiifolia frequently dot the surface. Borrichia arborescens 
also grows in numerous colonies on the sandy portions and as indi- 
vidual plants where the ground is rocky, as on the southern headland. 
Cactuses of the Opuntia type abound, but the Turk's-head Cactus 
did not come under my observation. 

All the above-named plants come down to the beach in places; 
but the most characteristic beach plants are Tournefortia gnaphalodes 
and Euphorbia buxifolia, species that seem able to hold their own 
on the most exposed beaches in these islands. Other typical beach 
plants such as Sccevola plumieri, Ipomoea pes-caprce, and Cakile 
lanceolata appear to be not so well adapted in this respect. The 
two first-named species were only represented by a few young plants 
growing amidst the beach-drift and a little above it on the east 
side of the principal isthmus. Of Cakile lanceolata I only found 
a solitary clump in the same locality. When the seas break across 
the low sandy necks during heavy weather most of the beach plants 
that have obtained a temporary footing are washed away. Sesuvium 
portulacastrum, a plant that is usually characteristic of beaches in 
this group, only presented itself in a solitary patch on the eastern 
beach. Uniola paniculata was scantily established on the lee or 
western side of the island. 

Cotton Cay. — Coming to the larger inhabited islands I will first 
allude to Cotton Cay. There is a house on the island, but it is not 
permanently occupied. However, sheep roam over most of its area, 
and " cultivations " of different kinds have been from time to time 
established and abandoned. I was not therefore disposed to take a 
special interest in this Cay, and limited my examination to a traverse 
across its centre and to a visit to the wind-swept eastern extremity 
where the original vegetation promised to be least disturbed. The 
island is about one and one-third miles long, 700 yards broad, and 
about forty feet high in the " rises " of seolian sandstone. But much 
of its area is low, the surface being in places rocky and around the 
two small central lagoons loamy and sandy. These lagoons are 



THE FLORA OF THE TURKS ISLANDS 283 



merely shallow ponds, which seem to have shrunk considerably in 
modern times. 

Conocarpus erectus was by far the most frequent constituent of 
the bush in the interior of the island, and the Turk's-head Cactus 
(Melocactus communis) was there not uncommon. Batis maritima 
and Salicornia ambigua covered the muddy borders of one of the 
lagoons that I passed near. On the beach on the south side were 
observed Suriana maritima, Borrichia arborescens, Ambrosia criihmi- 
folia, and Ipomcea pes-caprw. On the rocky eastern extremity 
were dense thickets of Coccoloba uvifera, the plants, owing to the 
exposure to the strong trade-winds, growing semi-prostrate or low 
and straggling. Here also Phyllanthus was common, and a few 
specimens of Genipa clusiifolia found shelter from the wind in the 
Coccoloba thickets. 

Salt Cay, the second largest island, is triangular in form, about 
three miles long and about one and one-third mile in greatest breadth. 
It reproduces the physical features of Grand Turk. With the 
exception of an elevated ridge of asolian rock, sixty feet in height, 
near its northern border and an isolated hill of the same height 
and composition towards its centre, most of it is raised only a few 
feet above the sea; and in the areas occupied by several lagoons 
and ponds, now shut off from the sea, its level must be below that 
of the ocean. There are extensive beaches backed by sand-dunes on 
the north, but bare rocky surfaces prevail over most of the rest of 
the island except around the lagoons where the ground is loamy or 
sandy. The salt industry has been pursued here with greater 
energy than in Grand Turk, and no doubt the establishment of 
salt-pans has quite changed the character of the vegetation in the 
interior. The mangroves have been nearly banished ; but in places 
around a large creek that communicates with the sea on the south- 
east side Rhizophora mangle, Avicennia nitida, and Laguncularia 
racemosa still survive, with extensive Salicornia colonies on the 
bordering mud-flats. 

Strand plants exist in profusion on the north and north-east 
sides of the island, both at the borders of the beaches and on the 
sandy dunes behind. Here flourish Suriana maritima, Tournefortia 
gnaphalodes, Conocarpus erectus, Euphorbia buxifolia, Ambrosia 
crithmifolia, and Ipomcea pes-caprae. Sccsvola plumieri is scanty 
in the island, but I found a fairly extensive colony on the beach 
near the southern point. A solitary patch of Canavalia obtusifolia 
was observed in the middle of the east coast. In the interior 
occur plants characteristic of Grand Turk, such as the Burnt-bush 
(Euphorbia vaginulata), Phyllanthus, etc. 

Grand Turk. — The flora of Grand Turk, the largest island of 
this small group, was first systematically examined by J. A. Hjalmars- 
son, who spent a fortnight there in 1858, as I learned from Dr. 
Millspaugh's manuscript, on his return from a botanical expedition 
in Haiti. Various new species from the interior of this island were 
described by Grisebach from Hjalmarsson's collections in his book 
on the West Indian flora. Their number has been increased in later 
years through the investigations of American botanists; but most 



284 PLANTS, SEEDS, AND CURRENTS 



of them exist on the adjacent islands of the Caicos Group and of 
the two Inaguas; and I should imagine that the south-eastern 
extremity of the Bahamian archipelago, consisting of the Turks, 
Caicos, and Inagua islands, will prove to be a subdivision of the 
floral region of the Bahamas. For years botanists from the United 
States have worked this region, and an authoritative discussion 
from the pens of Britton, Millspaugh, and others is to be expected, 
if it has not already been published. 

Generally speaking the flora of Grand Turk may be regarded as 
displaying a Bahamian impress in its interior and a West Indian 
impress at the coast. In other words, we can distinguish between 
the inland plants that give character to the larger islands of the group 
as a part of the Bahamian floral region and the strand plants, often 
monopolising the smaller cays, that are not only widely spread in 
the tropics of the New World, but are in not a few cases dispersed 
over the shores of the warm regions of the globe. Whilst the system- 
atist will be mainly attracted by the Bahamian facies and by the 
more specialised local features of the flora, the student of dispersal 
will be mainly interested in the plants of the strand. If the group 
consisted only of the small wind-swept and sea-swept cays a few 
hundred yards in length, its flora would have been almost entirely 
littoral and its general facies would be West Indian. It is the non- 
littoral vegetation of a large cay like Grand Turk that gives it its 
Bahamian impress and its still more localised characteristics. 

The topography of Grand Turk is also described in the chapter 
on the geology of the group. Here I will deal with it afresh, since it 
is necessary to bring into prominence features of more special interest 
in connection with the flora. The island is about five-and-a-half 
miles long and one to one-and-a-half miles broad, and attains a 
maximum height of about seventy- five feet. But much of its area, 
especially in the southern half, is raised only a few feet above the 
sea; and there are extensive portions below the sea-level that are 
occupied by the salt-ponds and the creeks which represent lagoons 
that once penetrated to the heart of the island. 

Two creeks communicating with the sea penetrate the north and 
south portions of the island. Both of them were doubtless at one 
time well lined by mangroves, which, however, have been largely 
cleared away from the North Creek, whilst in the South Creek they 
are still well displayed. North Creek, though nearly silted up at 
its mouth, is a clear sheet of water, about one-and-three-quarter 
miles long and 600 yards wide. South Creek is much smaller ; but 
doubtless it originally extended much farther into the island, as 
indicated by the " Great Salina " and other salt-ponds which reach 
to the centre of the island's length. The dams and other works 
carried out in connection with the salt industry have greatly changed 
the surface- conditions of the central part of Grand Turk; but it 
seems probable that originally South Creek extended as a chain 
of lagoons to the Town Pond in the middle of the island, and that 
the two creeks were only separated at their heads by a neck, not 
over a quarter of a mile broad, which is now represented by the 
low ridge dividing the Town Pond from the head of North Creek. 



THE FLORA OF THE TURKS ISLANDS 285 



Perhaps the most singular surface-feature of Grand Turk is the 
ridge of low hills of seolian sandstone, usually elevated fifty or sixty 
feet above the sea, that runs along the eastern border, completely 
obscuring, as the Rev. J. H. Pusey remarks in his handbook of the 
group, the eastern coast from the town or western shore. There 
are, however, other elevated portions or " rises," as in the north- 
west, south-west, and central districts of the island. 

The ground is occupied by open scrub all over the island, except 
in the parts where old or present attempts at cultivation have exer- 
cised disturbing influences, or where cattle have introduced new 
plants when brought to the island. Much of the surface, however, 
still illustrates the original condition of the open scrub vegetation 
that clothed it at the time of the first occupation by Europeans. 
The soil is loamy and sandy in the flats or lower levels, sandy on the 
gentle slopes of the hills, and rocky on the crests of the hills and on 
their steeper sides. The glaring whiteness of the sandy and loamy 
surface of the plains is often but partially relieved by the scrub 
that grows upon it. The soil is calcareous all over the island, and 
the proportion of humus is usually small. 

The Vegetation of Grand Turk. — I will deal in the first place 
with the plants of the sandy plains, then with those of the rocky 
upland districts and of other rocky localities, and lastly with the 
strand vegetation. 

1. The Plants of the Sandy Plains. — The scrub vegetation of 
the sandy plains and of the gentler hill- slopes in the interior of the 
island extends to the summit of the hills when the surface is sandy. 
Euphorbiaceous and Composite shrubs, with bushes of Lantana 
involucrata, and a pretty heath-like rubiaceous shrub, Borrera 
thymifolia, often form the greater part of the scrub. The Com- 
posite plants include Baccharis dioica and, as I was informed by 
Dr. Millspaugh, species of Pluchea. Amongst the Euphorbiacece 
the Burnt-bush (Euphorbia vaginulata) is the most conspicuous; 
but Croton hjalmarssonii, the Fire-shrub, and a Phyllanthus, probably 
P. epiphyllanthus, grow in quantities. Where the plains merge into 
the loamy flats bordering the salt-ponds and creeks Statice bahamensis 
thrives. The type of scrub vegetation as displayed on Grand Turk 
has a very peculiar aspect when the Burnt-bush abounds. Its 
dark hue, inconspicuous leaves, and black glands give this plant a 
sombre appearance, so that one might almost imagine that a fire 
had scorched the ground. If it were not for the variety afforded by 
the Borrera heath, the Lantana bushes, and the pretty Statice, the 
scrub of this island would present a very gloomy aspect in places 
where the Burnt-bush predominates. 

Although some of these scrub plants, like the Baccharis, the 
Phyllanthus, and the Lantana range widely in the West Indian 
region, several of them are purely Bahamian; and it is remarkable 
that this scrub flora of Grand Turk derives its special impress from 
species first described from this island, though but few of them 
have proved to be restricted to it. Thus, Euphorbia vaginulata, 
Croton hjalmarssonii, Borrera thymifolia, and Statice bahamensis 
were first described by Grisebach from specimens obtained by 



286 PLANTS, SEEDS, AND CURRENTS 



Hjalmarsson in the Turks Islands in 1858. Yet the first has since 
been gathered by Nash and Taylor (1904) in the two neighbouring 
islands of the Inaguas; the second by Britton, Millspaugh, and 
Hitchcock on Great Guana Cay and Fortune Island towards the 
middle of the Bahamas; whilst Borrera thymifolia and Statice 
bahamensis have probably been since found in the adjacent islands. 
It is, however, noteworthy that Dr. Millspaugh has described a new 
species of Euphorbia (E. lecheoides) from the sandy scrub-land of 
Grand Turk and Great Inagua (Prcenunc. Baham.). It would 
therefore seem that the endemism which the Turks Islands appeared 
at first to display in the scrub plants of the sandy plains is often 
shared with the adjacent islands, the Inaguas and probably also 
the Caicos Islands. 

Quite a character is given to the scrub vegetation of the plains 
in the southern part of Grand Turk by the strand plants that long 
ago deserted the beach and permanently established themselves 
inland. Here thrive amongst the ordinary scrub such typical 
shore shrubs and small trees as Dodoncea viscosa, Sophora tomentosa, 
and Coccoloba uvifera, of which only the last appears occasionally 
at the border of the beaches. It is not the occurrence of these 
plants in the sandy inland plains but the desertion of the shore that 
is difficult to understand. However, this matter will be mentioned 
again. Here one may notice that the Barbadoes Olive (Bontia 
daphnoides), which has probably been introduced, is one of the 
shrubs that are frequent in these southern plains. 

Another littoral plant frequent on the sandy soil of the interior, 
especially on the elevated northern end of the island, is Corchorus 
hirsutus. Borrichia arborescens, also a typical plant of the strand, 
often thrives at the foot of the hill- slopes, where they come down 
to the creeks and salt-ponds or descend to the beach. A small 
shrubby tree, known locally as the Manchineel, is also frequent on 
the lower slopes of the ridge bordering North Creek. It has the 
habit of the true Manchineel (Hippomane mancinella) and also several 
of the seed and fruit characters ; but its fruit is almost pyriform with 
pointed apex, and differs in other respects from the depressed globose 
fruit of the genuine species. The Manchineel proper, such as often 
came under my notice in other parts of the West Indies, did not 
present itself to me either on Grand Turk or in any of the other 
islands of this small group, though its fruits are one of the commonest 
constituents of the stranded drift. Dr. Millspaugh characterises 
it as a scrub-land plant widely spread in the Bahamas, including 
Grand Turk, where it was collected by Nash and Taylor in 1904 
(Prcenunc. Baham., I.). It is noteworthy that the Manchineel fruit 
of the Bahamas is described by Catesby as " shaped like a pear or 
rather a fig " (Nat. Hist. Carolina, Florida, and the Bahama Islands, 
II., 95, 1743). He saw very few of the trees and observed 14 none 
growing on the Sea-Shore." He attributes to them the usual 
qualities of the Manchineel proper; but it is evident that as in the 
case of the Grand Turk plant we are here dealing with quite another 
tree. 

2. The Plants of the Rocky Slopes and Ridges in the Interior of Grand 



THE FLORA OF THE TURKS ISLANDS 287 



Turk. — We are still concerned with scrub, but with scrub of a very 
different character from that found on the sandy plains, and with 
scrub that is in some localities almost arborescent. Many of the 
plants were strange to me. Probably the hilly district near the 
North Wells is most typical in these respects, and here the botanist 
would find his most interesting specimens. Here plants of the Cactus 
kind nourish, particularly Opuntia tuna and another species of the 
genus with very long spines, known as " Dildo." In such localities 
the Turk's-head Cactus (Melocactus) is at home, though now infre- 
quent, together with a smaller Cactus of similar form, perhaps a 
kind of Mamillaria. A species of Echites clambers over the rocks, 
and the Seven-year Apple (Genipa clusiifolia) grows sporadically 
on the stony crests of the ridges. The plant last named is also 
found amongst the detached rock-masses at the base of the bluffs 
facing the beach on the south-east coast. A fan-palm, perhaps a 
species of Thrinax, once grew as I was told in the north part of the 
island. Millspaugh in his Prcenuncice Bahamenses names several 
Bahamian plants of the Rubiacece collected by Nash and Taylor 
in the scrub of this island, such as Catesbcea campanulata, C. foliosa, 
Randia aculeata, Guettarda krugii, etc. ; and he describes a new species 
of the Euphorbiacece, Argythamnia argentea, which had been only 
found in the scrub-land of Grand Turk. Harshberger in his general 
work (p. 694) refers to a shrubby Pithecolobium, ten to fifteen feet 
high, as growing on this island. 

Spiny Acacia trees and shrubs, including Acacia farnesiana, A. 
acuifera, and one or two other species, grow in places, as on the lower 
ground of the North Wells district. Acacia farnesiana may have 
been introduced by cattle. A. acuifera was first described by 
Bentham from Hjalmarsson's collections in the Turks Islands. 
I gathered from Dr. Millspaugh' s manuscript that it is peculiar to 
the Bahamas, being found also on the islands adjacent to the Turks 
Group, namely, the Caicos Islands and the two Inaguas. Here and 
there amidst the rocks of the ridges thrives Guilandina bonducella, 
which on Grand Turk has practically abandoned its customary 
station amongst the vegetation bordering the beach. Thespesia 
populnea is another plant that has to a great extent deserted its 
littoral station on Grand Turk. One side of the North Wells hollow 
is bordered by a copse of these trees situated about a third of a 
mile from the beach, where they are still scantily represented. 

I have now gone far enough to illustrate the general character 
of the flora of the sandy plains and rocky slopes and ridges in the 
interior of Grand Turk. We find here plants that the Bahamas 
hold in common with other West Indian localities, plants that are 
widely spread over the Bahamas but are confined to that archipelago, 
plants restricted to the extreme south-eastern islands (the Caicos 
and Turks Islands and the Inaguas) and held in common by them, 
and plants found only in the Turks Islands, as represented by Grand 
Turk. Though the endemism of the Grand Turk plants is probably 
not very great, it is sufficient to convince us that we are concerned 
here with ancient conditions of isolation. 

3. The Strand Plants of Grand Turk. — We are concerned here with 



288 PLANTS, SEEDS, AND CURRENTS 



plants, most of which the writer was familiar with in the West Indies 
and in other parts of the tropics. The question of endemism is not 
here raised, as all of them occur outside the Bahamian area. But 
two points require a preliminary notice. In the first place, as already 
remarked, a number of the plants have largely deserted the beach, 
though they are typical shore species in other regions. In the 
second place, the littoral flora often receives accessions from the 
scrub of the interior. The shore plants that are rare on the beach 
and are found thriving in the scrub of the interior are Coccoloba 
uvifera, Dodoncea viscosa, Guilandina bonducella, and Sophora 
tomentosa, and to these may be added Thespesia populnea, as it grows 
around the North Wells. When they appear at the beach-border 
it is only as representatives of the seaward extension of the plants 
of the plains and of the hill-slopes. Of the characteristic plants 
of the interior that at times establish themselves on the beach, 
Euphorbia vaginulata, the Burnt-bush, is the most conspicuous. 
But amongst the other plants of the scrub of the inland plains that 
are not infrequently to be observed mingled with the true beach 
plants on the sandy tracts that lie in the rear of the beach are Borrera 
thymifolia, Lantana involucrata, and Phyllanthus epiphyllanthus. 
Whether the typical shore plant penetrates into the plains or whether 
the characteristic plant of the inland scrub intrudes on the beach, 
it is merely a matter of xerophytes seeking another suitable station. 
The influences that tend to keep apart the xerophytes of the plains 
and the xerophytes of the beach are concerned rather with the plant's 
capacity for dispersal than with differences in station. 

The beach that extends for miles along the eastern border of the 
island affords excellent opportunities for the study of the arrange- 
ment of the strand plants. A sandy, dune-like tract, usually about 
fifty yards in breadth, separates it as a rule from the line of bluffs 
of seolian sandstone that runs along the length of Grand Turk. At 
times, however, the bluffs advance to the beach-margin ; and again, 
as in the south, they may recede 100 yards or more inland. Al- 
though it is often easy to detect a method in the arrangement of 
the plants of the beach and of the dune-belt behind, the plants 
mingle together as one approaches the bluffs, and at the foot of these 
cliffs they grow side by side with the scrub plants of the inland plains. 

Walking inshore from the high-water level we first meet with 
Ipomcea pes-caprce and Sesuvium portulacastrum, which soon give 
place to clumps of Euphorbia buxifolia and Cakile lanceolata. A few 
paces back, where the beach proper joins the duny sand tract, we 
notice that the foremost mounds are held by the silver-grey shrubs 
of Tournefortia gnaphalodes and the bright-green plants of Scmvola 
plumieri. Dark clumps of Suriana maritima with its broom-like 
habit cover the mounds behind, and the ground we tread upon is 
carpeted with Ambrosia crithmifolia. Such is the usual order in 
which the plants present themselves as we walk in from the beach; 
but they all mingle together as we cross the rolling, sandy tract 
towards the inland bluffs, at the foot of which they intermingle 
with the scrub vegetation of the interior as before described, and 
make but scanty efforts to ascend the sandy and rocky slopes. 



THE FLORA OF THE TURKS ISLANDS 289 



One may notice here an interesting plant which, though not 
strictly a shore plant, is most at home when clambering over the 
shrubs in the broad, rolling, sandy belt that lies behind the beach 
at the south end of the island. This is Passifiora pectinata, which 
was first described by Grisebach from Hjalmarsson's collections 
on Grand Turk. It is apparently restricted to the Bahamas. Though 
at first sight the fruits of Passifiora would not appear suitable for 
distribution by currents, it is evident that they can be carried short 
distances, and reference is made in Chapter II. to their occurrence 
amongst the beach-drift on the south coast of England in different 
years. However, the seeds have no buoyancy except when air- 
bubbles adhere to them in the dry state, or when the nucleus is decaying 
or has decayed. But the fruits would not long endure the " rough- 
and-tumble " of an ocean traverse. They owe their floating power 
to the buoyancy of the thick rind, which is covered by a tough skin. 
It is also possible that birds might aid in the oversea transport 
of the seeds, which are sufficiently protected by their crustaceous 
shells to be able to withstand a passage in a bird's stomach or in- 
testines. In this connection it is noteworthy that Mr. Savage 
English remarks in the case of the island of Grand Cayman that 
" Passifiora cuprea, L. (a Bahamian, Cuban, and probably also a 
Jamaican species), has apparently been brought by a bird within 
the last few years, and is certainly being rapidly spread (in the island) 
by this means " (Kew Bulletin, 1913, p. 368). 

The Mangroves of Grand Turk. — In the development of the salt 
industry, which has been established here since the seventeenth 
century, there has been a great clearance of the mangroves. Whilst 
in the case of Salt Cay the mangroves have been from this cause 
nearly banished from the island, there is a considerable remnant in 
Grand Turk of the extensive mangrove belt that must have originally 
lined all the creeks and lagoons. It is well represented in South 
Creek ; but most of the mangroves there appeared of recent growth, 
and I was told that up to late times there have been large clearances 
made here. But the mangrove belt soon grows again. However, 
in 1911 its appearance in South Creek gave one an idea of its original 
condition. Near its mouth South Creek is fringed by a dense belt 
of Rhizophora mangle backed on the landward side by Laguncularia 
racemosa, Avicennia nitida, and occasionally Conocarpus erectus. 
However, isolated patches of mangrove here extend into the heart 
of the island on the shores of shallow lakelets, which no doubt at 
times are in communication with South Creek. In North Creek 
at the opposite end of the island mangrove is very scanty. There 
are patches of Rhizophora and Avicennia at its mouth, with some 
Avicennia trees on the west shore and one or two at the head. Lagun- 
cularia is very rare at North Creek. I only saw one tree. 

A curious mingling of mangroves with the beach flora and with 
plants of inland plains is to be noticed occasionally on Grand Turk, 
where the sea-beach and the lagoon borders meet at the foot of a 
slope. Here Rhizophora mangle, Laguncularia racemosa, Avicennia 
nitida, Suriana maritima, Coccoloba uvifera, Borrichia arborescens, 
and Euphorbia vaginulata grow together on the loamy mud-flat, 
u 



290 PLANTS, SEEDS, AND CURRENTS 



Halophytes grow in abundance on the muddy shores of the creeks 
and salt-ponds of Grand Turk. The most frequent are Batis mart- 
tima, Salicornia ambigua, and a species of Sesuvium, with a species 
of Suceda in places, and Borrichia arborescens at the landward border 
of the flats. 

The Introduced Plants of Grand Turk. — I need only refer here 
to the plants of waste ground which the white man has spread over 
the tropics, such as Argemone mexicana, Datura stramonium, Ricinus 
communis, and Vinca rosea. One of the first things to attract the 
notice of the stranger when he lands at the town is an extensive 
bank of Calotropis procera on the sea-front. 

Endemism and Isolation in the Turks Islands. — The data at my 
disposal only allow of a brief reference to this subject and in a 
tentative fashion. The bathymetrical surroundings of the Turks 
Islands are discussed in the chapter on the geology of this small 
group. It is highly probable that as a unit in the great Bahamian 
archipelago the Turks Bank has always maintained its isolated 
condition. North and south the submarine slopes descend to depths 
of 2000 fathoms and over. The broad trench dividing the Turks 
Bank from the Caicos Bank on the west must be about 1500 fathoms 
deep opposite the two banks ; but they are connected to the south- 
ward by a " col " covered by 1500 feet (250 fathoms) of water. Yet 
this is the only evidence of a former possible connection with existing 
land-surfaces, since away to the eastward stretch three submerged 
banks which, except on the Turks Group side, are surrounded by the 
ocean's depths. In these respects the isolation of the Turks Islands 
is typical of the eastern Bahamas, where the banks on which the 
islands rise may be separated by depths of 1000 to 2000 fathoms. 
Endemism ought, therefore, to be well displayed in the Bahamian 
archipelago, more especially in the east; but it would be kept in 
check by the monotony of the climatic, geological, and soil con- 
ditions. It is exhibited in the plants, the land-molluscs, and the 
reptiles, but with a special Bahamian impress. Several of the 
plants first described from the Turks Islands have been found in 
the neighbouring islands, and it seems likely that the leading feature 
of the endemism of this small group is that which it shares with the 
Caicos Islands and the two Inaguas. There has been constant 
intercourse between them for the last two centuries and more, and 
it may be that the aborigines during earlier periods aided in bringing 
about the mingling of their respective floras. 

The Flora of the Turks Islands from the Standpoint of Dispersal. — 
The plants fall conveniently into two groups, those of the shore and 
those of the inland scrub. The former are not only found over the 
West Indian region, but often also in the Old World. The latter 
are all plants of the New World, some occurring also in the other 
West Indian islands, others widely spread over the Bahamas and 
confined to that archipelago, others confined to, but held in common 
by, the Turks and Caicos Islands and the two Inaguas, and a few 
restricted to the Turks Group. 

The shore plants found in the Old World include — 
Avicennia nitida (Currents). 



THE FLORA OF THE TURKS ISLANDS 291 



Canavalia obtusifolia (Currents). 
Cenchrus echinatus (Birds, in plumage). 
Conocarpus erectus (Currents). 
Cor chorus hirsutus (Drifting logs and man). 
Dodoncca viscosa (Currents, man, etc.). 
Guilandina bonducella (Currents). 

Heliotropium curassavicum (Floating logs, pumice, man). 

I pom as a pes-caprce (Currents). 

Laguncularia racemosa (Currents). 

Portulaca oleracea (Floating logs, pumice, man). 

Rhizophora mangle (Currents). 

Sccevola plumieri (Currents and frugivorous birds). 
Sesuvium portulacastrum (Floating logs, pumice, man). 
Sophora tomentosa (Currents). 
Suriana maritima (Currents and floating logs). 
Thespesia populnea (Currents and man). 

The shore plants confined to the New World, and as a rule widely- 
spread over the West Indies, include — 

Ambrosia crithmifolia (Drifting logs and man). 

Batis maritima (Currents and man). 

Borrichia arbor escens (Drifting logs and man). 

Cakile lanceolata (Currents for a few hundred miles). 

Coccoloba uvifera (Currents and frugivorous birds for distances 
not exceeding 200 miles). 

Cyperus brunneus (Birds, per pedes et intestina, Millspaugh). 

Ernodea littoralis (Frugivorous birds; capacity for dispersal 
by currents not tested). 

Euphorbia buxifolia (Attached to feet of birds, Millspaugh; 
probably also drifting logs and man). 

Genipa clusiifolia (Currents to a small extent, iguanas, frugivor- 
ous birds, and man). 

Ipomoea tuba (Currents. It is regarded by Urban as also an 
Old World plant). 

Rhachicallis maritima (Means of dispersal unknown, but pro- 
bably not by currents). 

Salicornia ambigua (Currents, feet of birds, man. By some 
regarded as a form of S.fruticosa, an Old World species). 

Tournefortia gnaphalodes (Currents). 

Uniola paniculata (Regarded by Millspaugh as dispersed by 
currents; but no experiments have been made, and pro- 
longed floating powers seem unlikely). 

(Most of these plants are specially discussed in other pages of this 
work. Some of the small seeded species are dealt with in Note 21 
of the Appendix, and others like Batis maritima in my work on 
Plant Dispersal.) 

The association of considerable powers of dispersal by currents 
with existence in the Old World is especially noteworthy. Three- 
fourths of the littoral shore plants that occur not only all over the 



292 PLANTS, SEEDS, AND CURRENTS 



West Indian region but also in the Old World possess this capacity, 
the others being mostly small-seeded plants, where the seeds are 
non-buoyant. In the case of the shore plants confined to the New 
World there are only four that could be transported over great 
distances by the direct agency of the currents, namely, Ipomoea tuba, 
Salicornia ambigua, Batis maritima, and Tournefortia gnaphalodes ; 
and it is remarkable that in the first two plants their restriction to 
the New World is disputed, their fitness for trans-oceanic dispersal 
making a silent appeal against the narrower view of their range. 
For the other plants we have to invoke a variety of agencies, such 
as birds in different ways, floating logs, pumice, and man. 

Of the capacity for dispersal by currents possessed by the plants 
of the scrub in the interior of the islands I have very few direct data. 
The few that were in immature seed gave little promise of such a 
capacity ; but from my extended experience of the buoyant behaviour 
of seeds it may be inferred that as in other localities the inland plants 
have in the mass been brought here by other means. Neither the 
grasses nor the sedges would, it is probable, have been aided in this 
way, and doubtless they have often been brought by birds. It is 
most likely that frugivorous birds would account for the presence 
of Lantana involucrata, Melocactus communis, and Pithecolobium ; 
whilst the small seeds or seed-like fruits of the other plants are 
probably indebted for their presence here to granivorous birds. 
The species of Corny ositce (Baccharis dioica and Pluchea) may possibly 
have been aided by the strong winds, their fruits being provided 
with a pappus. I have no data relating to the genus Phyllanihus, 
of which two species (P. epiphyllanthus, L., and P. niruri y L.) are 
known from the islands (Millspaugh's Prcenunc. Baham.). 

(Particulars of the works quoted in this chapter will be found in 
the list of references at the beginning of this volume.) 

Summary 

1. The vegetation of the Turks Islands, apart from the littoral 
plants, is generally sparse and of the scrub type, the soil being 
usually sandy. 

2. Beginning with the smaller cays, they are described as mainly 
occupied by West Indian strand plants, the true scrub-land species 
presenting themselves in the larger islands. Amongst the islands, 
Greater Sand Cay is regarded as of special interest, since it is the 
first to catch the floating drift and illustrates a stage in the plant- 
stocking intermediate between that indicated in the small cay a 
few hundred yards in length and that exemplified in Grand Turk, 
which is five to six miles long (p. 278). 

3. After referring to the work of American botanists (p. 283), the 
plants of Grand Turk are dealt with more in detail. Its flora derives 
its Bahamian impress from the plants of the inland scrub, and its 
general West Indian impress chiefly from the plants of the strand 
(p. 284). 

4. Having described the topography of the island (p. 284),the author 
deals with the scrub vegetation, first of the inland sandy plains 



THE FLORA OF THE TURKS ISLANDS 293 



( p . 2 85 ) and then of the rocky upland and the rocky lower levels ( p .28 6 ) . 
It is, however, shown that in the southern end of the island quite 
a character is given to the vegetation of the sandy plains by the 
abundance of a number of shore shrubs that have largely deserted 
the beach (p. 286). 

5. As far as the data at the writer's disposal enable him to form an 
opinion, they indicate in the case of the inland scrub flora that whilst 
some species occur in other parts of the West Indies, others are 
restricted to the Bahamas as a whole. Some, again, are confined 
to the Turks Islands with the neighbouring Caicos and Inagua 
groups, and, lastly, a few are peculiar to the Turks Islands (p. 287). 

6. With regard to the strand plants of Grand Turk, it is remarked 
that the question of endemism is not here raised, since practically 
all of them occur outside the Bahamas and not infrequently also in 
the Old World, a conclusion which applies to the true littoral flora 
of the Turks Group as a whole (p. 288). Whilst not a few of the shore 
plants invade the inland plains, some of them having almost deserted 
the beach, the plants of the inland scrub may in their turn intrude 
on the beach, mingling there with the characteristic strand flora. 
Here the xerophytes of the plain and the xerophytes of the strand 
experience little difficulty in exchanging their stations, the influences 
that tend to keep them apart being more concerned with fitness 
for dispersal by currents than with station (p. 288). The general 
arrangement of the plants on the beach-border is then described 
(p. 288). 

7. After mentioning the occurrence of a peculiar Bahamian species 
of Passiflora in the dune district behind the beach (p. 289), the halo- 
phytes of the muddy shores of the creeks and lagoons are named 
(p. 290). 

8. The mangroves, which once formed extensive swamps on 
Grand Turk, Cotton Cay, and Salt Cay, and are still fairly represented 
on Grand Turk, are described. The clearings connected with the 
establishment of the salt-ponds have almost banished them from 
the other islands (p. 289). 

9. It is argued that the endemism favoured by the great depths 
between and around the Bahamian islands would be checked by 
the monotonous character of the climate, geological structure, and 
soil conditions over the archipelago (p. 290). 

10. With regard to the means employed by Nature in stocking 
the Turks Islands, it is observed that two-thirds of the littoral plants 
that are found in the Old World could have been directly brought 
there by the currents. For the shore plants confined to the New 
World, we have usually to appeal to the bird, to the drifting log, 
and to man. In the case of the inland scrub plants birds are probably 
the chief agents of distribution. 



CHAPTER XIII 



THE CURRENT-CONNECTIONS IN THE SOUTHERN HEMISPHERE 

In this chapter are discussed the current- connections between the 
three great land-masses of the southern hemisphere, South America, 
Africa, and Australia. The matter is scarcely germane to the subject 
proper of this work; but, in the light of my own consideration of 
the problems involved, I will briefly state the results obtained from 
the bottle-drift data supplied by Schott's memoir and from other 
sources. 

The Relationship between the Southern Floras. — It is 
well known that there is a very interesting relationship between the 
floras of these three widely separated regions, a subject which has 
occupied the attention of Hooker, Grisebach, Engler, Drude, Schimper, 
Hemsley, and many others. One of the most important of recent 
contributions to the literature of the matter, though more concerned 
with animals than with plants, is Mr. Hedley's paper on the palaeo- 
geographical relations of Antarctica (Proc. Linn. Soc. Lond., June 
6, 1912). 

A common source in the northern hemisphere would explain the 
presence in these land-masses of the south of several of the genera, 
such as Fagus, Podocarpus, Araucaria, etc. ; and here we are simply 
assuming that the same principle which has been at work in recent 
times within the lives of existing species of Sphagnum and Carex 
(see Chapter XVI.) operated also in past ages. Birds would explain 
the occurrence of the same species of Accena, Cotula, Nertera, Uncinia, 
etc., in the extra- tropical portions of these areas ; and currents would 
account for the existence of the same littoral plants, such as Sophora 
tetraptera, Convolvulus soldanella, and perhaps Sicyos angulatus, 
in regions separated by thousands of miles of ocean. It would, 
however, be in the tropics that the currents would be most effective 
in accounting for the occurrence of the same species of shore plants 
on the opposite sides of the oceans. 

The Drift round the Globe in High Southern Latitudes. — 
Before dealing with the current-connections of the southern hemi- 
sphere I will refer to one of the most interesting phenomena concerned 
with the currents of the globe, namely, the drifting round the earth 
in high southern latitudes of bottles and wreckage. The subject 
is one that could be treated in great detail. Here, however, it 
will be only dealt with in an illustrative fashion, and the leading 
considerations that arise will be presented in a general way, thus 
introducing the discussion that follows. 

294 



CURRENT-CONNECTIONS IN S. HEMISPHERE 295 



On the southern and south-eastern coasts of Australia, and even on 
the north-east shores of the island continent, there are stranded bottles 
and wreckage from off Cape Horn and from the vicinity of the islands 
of the Southern Ocean lying north of Kerguelen, such as the Crozets, 
St. Paul's, and Amsterdam. Roughly speaking, between the parallels 
of 40° and 60° S. lat. the never-failing westerly winds establish a 
surface current around the globe, known as the West Wind Drift 
Current. Of some sixteen bottles referred to in Schott's memoir 
which performed long passages of from 3500 to 8500 miles in these 
latitudes, all took an easterly course before the winds of the Roaring 
Forties. There is not an exception; and the same remark applies 
to numerous bottles in Australian waters south of the 40th parallel, 
for the particulars of which we are indebted to Russell, whose " cur- 
rent papers 55 in the Journal of the Royal Society of New South 
Wales for 1894 and 1896 are utilised by Schott. 

The average minimum drift-rate up to the dates of the recovery 
of the bottles is eight to nine miles a day. The quickest rate is 
concerned with one that covered the distance of about 4500 miles 
between a locality to the north of Kerguelen and its place of arrival 
in New Zealand at a speed of at least 10-6 miles a day. If in order 
to allow for the delay in the recovery we take the average daily rate 
at ten miles, then a bottle drifting round the globe, so as to clear 
Cape Horn, would accomplish the circuit of about 12,000 miles in 
rather over three years. At this speed a bottle starting from off 
the Horn would reach South-eastern Australia in about two and a 
third years, a passage of about 8500 miles. Two mentioned by Schott 
actually accomplished this traverse, the minimum daily rates up 
to the dates of recovery in South-east Australia being 8 and 9*2 
miles. One, referred to by Page, even extended its drift around 
the east coast of Australia to Cape York, performing a passage of 
some 10,500 miles in nearly three years at a minimum rate of about 
ten miles a day, one of the longest drifts known. 

But the important point is that during the easterly drift across 
the Southern Ocean there is a continuous slant to the northward. 
Drift always decreases its latitude during long passages in the belt 
of the " brave west winds " ; and its general course from off Cape 
Horn towards Australia would be about E. by N. and from New 
Zealand eastward about E. \ N. Thus it is that bottles and wreckage 
from off the Horn in about lat. 57° S., from the vicinity of the Crozets 
and northward of Kerguelen in lat. 44°-46° S., and from the seas 
to the south-west of Cape Leeuwin in lat. 42° S., in all cases cross 
the 40th parallel before reaching Australia. The same northward 
deflection is to be noticed in drifts across the Pacific in high latitudes, 
but the amount is less, the displacement being from two to five 
degrees of latitude. 

Schott (p. 22) emphasises this northerly slant of the drift in the 
Southern Ocean. The result is that Fuegian drift reaches the south 
coasts of Australia and the north extremity of New Zealand, which 
lie fifteen to twenty degrees further north. Of four bottles cast 
overboard off Cape Horn, three of which are referred to by Schott 
and one by Page, one reached South-west Australia in the vicinity 



296 PLANTS, SEEDS, AND CURRENTS 



of Albany, two reached South-east Australia to the eastward of 
Melbourne, and one, already mentioned, rounded the south-east 
corner of the island continent and reached Cape York, the most 
northerly point of Queensland. The figurehead of the Blue Jacket, 
a ship that was burned between the Falkland Islands and Cape 
Horn in lat. 53° S. and 60° W. in March 1869, was recovered at the 
beginning of 1872 at Fremantle in West Australia. This is the only 
" drift record " at my disposal that illustrates the branching north 
from the West Wind Drift Current, as it approaches Cape Leeuwin, 
of the West Australian Current. It is quoted by Schott (p. 23) 
from the Melbourne Argus for March 28, 1872. 

Fuegian Drift. — If it were possible for Fuegian drift to be 
carried round the earth and back to the western side of South America, 
it would strike the coast about twenty degrees north of its original 
starting-place. A bottle commencing its voyage round the globe 
from Cape Horn would under these conditions be ultimately stranded 
on the shores of the same continent somewhere between Valdivia 
and Valparaiso. If practicable, this passage of about 15,000 miles at 
an average speed of ten miles a day would occupy about four years. 
However, Russell's numerous observations in Australian waters 
demonstrate its impracticability. Fuegian drift after brushing 
past the coasts of South-eastern Australia and Tasmania would, 
if it escaped stranding on the north end of New Zealand, be carried 
to the north-east for a short distance. It would then come within 
the influence of currents setting to the westward and northward 
that would sweep it back on the coasts of Queensland, of which an 
actual instance has before been given as supplied by Mr. Page. 
The westerly set of the currents between Fiji and the Kermadec 
Islands would effectually block the passage of Fuegian drift across 
the Pacific, and it would similarly prevent the passage eastward to 
South America of any Australian drift. This point is well illustrated 
in one of Schott's bottle-drift charts (Table 6). 

It is apparent from the tracks of bottles laid down in Schott's 
charts that whilst Fuegia could distribute drift to South Africa, the 
Crozets, St. Paul, and Amsterdam Islands, the southern coasts of 
Australia, Tasmania, and the northern extreme of New Zealand, 
it could do little more, since the rest of the materials would be swept 
back to the Queensland coasts. On rare occasions by making an 
unusually wide detour some Fuegian drift might be stranded on Nor- 
folk Island and New Caledonia before it was turned back by the 
Southern Equatorial Current ; but that would be the extent of its 
invasion of the Pacific Ocean. 

The only drift that could reach Fuegia from the west would be 
derived, as will subsequently be shown, from the southern end of 
New Zealand, from the Antarctic islands lying south of it, from 
Kerguelen and the islands to the south of it, from the distant South 
Shetland and South Orkney Islands, and from the coasts of the 
Antarctic continent adjacent to the two groups just named. None 
of the drift from the vicinity of Cape Horn could ever return to the 
South American continent ; and if any floating objects ever performed 
the circuit of the globe in these high latitudes it would be south 



CURRENT-CONNECTIONS IN S. HEMISPHERE 297 



of the 60th parallel. The bearing of these considerations on the 
distribution of littoral plants in the Southern Ocean will be sub- 
sequently discussed. 

The Current-Connections of Australia. — I will now deal 
separately with the current- connections of the great land-masses 
of the southern hemisphere as far as they throw light on the distri- 
bution of littoral plants in those regions; and in the first place I 
will take Australia. The island continent is peculiarly situated 
in these respects. Whilst from its tropical north-west shores it 
would distribute drift across the Indian Ocean to the East African 
coasts, on its south-west border and along the whole length of its 
southern coasts it would receive drift, occasionally from South Africa, 
but more usually from Fuegia and the intervening islands of the 
Southern Ocean. From its south-eastern coasts it would supply 
materials to the northern end of New Zealand ; whilst on its middle- 
east and north-east coasts would be stranded drift from the islands 
of the tropical South Pacific and from Equatorial South America. 
The only materials it could receive from New Zealand would be 
derived from the vicinity of the North Cape. Such drift, as is shown 
below, would be thrown up on the coasts of Queensland, where it 
might even be associated, as previously implied, with drift brought 
from Fuegia by the West Wind Current. 

Dealing first with the eastern coasts of Australia, the data in 
Schott's memoir indicate that we are more especially concerned with 
the shores of Queensland along its length and with the transporting 
agency of the South Equatorial Current. Bottles have been re- 
covered on the Queensland coasts not only from the region between 
and including Fiji, Tonga, and Norfolk Island, but from off the 
distant coast of Ecuador on the other side of the Pacific; and it 
may be safely assumed that the eastern archipelagos of the South 
Pacific, the Marquesan, Paumotuan, and Tahitian groups, which 
lie athwart the track of the trans-Pacific traverse, would also supply 
drift to the Queensland coasts. 

The principal data, on which the remarks just made are based, 
may here be given. A bottle cast overboard about 250 miles from 
the coast of Ecuador in lat. 3° 52' S. and long. 85° 38' W. was recovered 
966 days afterwards near Cooktown in North Queensland, the 
traverse of J7620 miles, as estimated by Schott, having been accom- 
plished at a minimum rate of 7-9 miles a day (Schott, pp. 24, 27, 
Chart 6, No. 33). The same traverse was in part accomplished in 
mid-ocean by three bottles mentioned by Schott (p. 24, Chart 6, 
Nos. 6, 7, 40), which were found in the Paumotus after covering 
distances of from 1600 to 2100 miles, having been dropped overboard 
in the Eastern Pacific between the parallels of 10° and 12° S. These 
bottles, being outside the swiftest part of the current, gave a drifting 
rate of only five miles a day. An interesting traverse in mid-ocean, 
but more to the north and near the axis of greatest velocity of the 
South Equatorial Current, is mentioned by Page. Here a bottle, 
dropped overboard on January 23, 1897, in lat. 4°N. and 168° W. 
was found on the Gilbert Islands forty-two days afterwards, having 
drifted 1100 miles at the rate of twenty-six miles a day, the fastest 



298 PLANTS, SEEDS, AND CURRENTS 



record for its distance known from this part of the Pacific. Had 
this bottle pursued an uninterrupted course, it would probably, 
after traversing the Solomon and Lousiade Archipelagos, have been 
stranded on Cape York Peninsula. The last part of the ocean- 
crossing was effected by four bottles which reached the coasts of 
South Queensland and those of New South Wales, just across the 
border, from the region of the Western Pacific comprised between 
the Fijian and Tongan Groups and Norfolk Island (Schott, p. 24, 
Chart 6, Nos. 8, 9, 18, 25). 

The evidence afforded by the nine bottle-drifts above dealt with 
is clear and consistent. All tell the same story and indicate in no 
doubtful manner the probability of drift seeds from tropical South 
America reaching the tropical and subtropical shores of Eastern 
Australia. The extent to which the distribution of littoral plants 
in these two widely separated areas responds to the influence of the 
South Equatorial Current will be subsequently noticed. But the 
east coast of Australia has other possible current- connections which 
have been before mentioned. It is evident from the data supplied 
by Russell and Schott that the branch of the West Wind Drift 
Current which proceeds through Bass Straits on its way towards 
the North Cape of New Zealand is deflected to the northward and 
westward, sometimes before and sometimes after passing that head- 
land; and the bottle- drift tracks indicate that materials washed 
off the North Cape would be stranded in the vicinity of Brisbane. It 
would thus appear that the coasts of Queensland would be the recipient 
of drift from the extreme north of New Zealand. It would also, as 
shown by the stranding of the bottle from Cape Horn on the Cape 
York Peninsula, receive Fuegian drift. 

Coming to the southern sea-borders of Australia, we have already 
referred to the fact that bottle-drift and wreckage from Fuegia, 
from the Crozets, and from the islands north of Kerguelen may be 
thrown up on these shores. But the south coasts of Australia may 
also at times receive drift from South Africa. A bottle cast over 
about seventy miles south-east of Cape Agulhas was recovered on 
the coasts of the Great Australian Bight (Schott, Map 5, No. 31). 
The tropical north-west sea-borders of the island continent have 
doubtless received many of their littoral plants from the neighbouring 
Malayan region through the agency of the currents. They would, 
as is shown on a later page, distribute drift through the South 
Equatorial Current to the coasts of tropical and extra-tropical 
East Africa. It is possible that materials would be also received 
from the branch of the West Wind Drift Current proceeding north 
from Cape Leeuwin, which is known as the West Australian Current. 
But from the standpoint of distribution any seed- drift from high 
latitudes on the Southern Ocean would be ineffective in those warm 
regions. It is, however, likely that seed-drift from this source 
would be effective on the coasts of extra-tropical Western Australia, 
and we have already seen, in the case of the stranding near Fre- 
mantle of the figurehead of a ship burned at sea between Cape 
Horn and the Falkland Islands, that drift may reach those shores 
from the southern extreme of South America. 



CURRENT-CONNECTIONS IN S. HEMISPHERE 299 



New Zealand as a Receiver and Distributor of Drift. — 
This subject has already been several times mentioned in this chapter. 
Whilst its north-west shores would receive drift from Southern 
Australia and Tasmania, they would also receive the tailings of 
drift from Fuegia and the islands of the Southern Ocean (north 
of Kerguelen) that had slipped past the Australian and Tasmanian 
coasts. On its south-west shores would be stranded materials 
from Kerguelen and the islands south of it, and perhaps also some 
occasional drift from the islands (South Shetlands and South Orkneys) 
and the adjacent coasts of the Antarctic continent south of the 
Horn. 

Russell, as quoted by Schott (p. 23), gives a number of examples 
to show that bottles thrown over south of the 40th parallel between 
Tasmania and New Zealand arrive in almost every case at the western 
shores of New Zealand. Some longer drifts, as supplied by 
Schott in his charts (5 and 6) and as mentioned in his text, are worth 
remarking. Thus, a bottle (No. 17) thrown over to the S.S.W. of 
Cape Leeuwin in about lat. 41° 30' was stranded close to the North 
Cape. Another (mentioned by Russell) thrown into the sea more 
to the south-west in about lat. 46° S. and long. 103° E. was recovered 
on the south-east coast of New Zealand, after doubling the South 
Cape. A third (No. 21) from a position about 200 miles north-east 
of Kerguelen and near the 46th parallel was beached at the entrance 
to Cook Straits. 

That the southern extremity of New Zealand may receive drift 
from higher latitudes is indicated by the record of a cask which is 
noted by Schott on p. 23. Derived from the whaler Ely, which 
was lost on the Macdonald Islands to the south of Kerguelen in 
about lat. 53° S., it was ultimately found on the Chatham Islands, 
a period of 510 days having passed since the loss of the ship. As 
a distributor of drift to the Pacific coasts of extra-tropical South 
America, New Zealand plays an important part, a matter that is 
discussed below. The possibility of drift washed off its northern 
extremity being carried to Queensland has already been noticed. 

South America and its Current-Connections. — The circum- 
stance that South America reaches south to the 56th parallel, whilst 
New Zealand extends to about the 47th and Africa only to the 35th, 
has been a determining feature in plant distribution in this part 
of the globe. To this factor in the dispersal of plants by currents 
must be added another determining influence due to the northern 
slant of the easterly drift in the higher southern latitudes. For 
this reason Australian drift could never be carried to corresponding 
latitudes on the Pacific side of South America ; and, as we have seen, 
its traverse of the Pacific Ocean would under any circumstances 
be impossible on account of the working of the currents to the north 
of New Zealand as interpreted by the bottle-drift data. 

On the other hand, materials from the southern end of New Zealand 
and from the Antarctic islands to the south of it would be stranded 
on the shores of South Chile between Valdivia and the island of 
Chiloe, 40°-43°S. The course that such drift would take is ex- 
emplified by the track of a bottle, which, after being cast overboard 



300 PLANTS, SEEDS, AND CURRENTS 



in the middle of the South Pacific in about lat 46° S. and long. 135° W., 
was picked up on Chiloe (Schott, p. 22, Map 6, No. 38). Materials 
from the islands south of New Zealand, such as Auckland and Mac- 
quarie Islands, from Kerguelen and the islands south of it, and 
from perhaps the distant South Orkney and South Shetland Islands 
and the neighbouring shores of Antarctica, would be beached further 
south on the coasts of Fuegia and on the islands reaching north 
from Cape Pillar to the 50th parallel. A very interesting drift- 
record was published in the London Times for April 17, 1912. A 
bottle thrown over by Captain Wilkes of the Tyser Line nearly a 
thousand miles east of Kerguelen (lat. 51° 38' S. and long. 96° 15' E.) 
on November 17, 1908, was recovered about three years afterwards 
by Maurice Deffarges on the coast of South Chile in lat. 49° 42' S. 
and long. 74° 25' W. 

Doubtless drift materials brought from high southern latitudes 
by the " west wind drift current " to these shores of South America 
would sometimes be carried north by the Humboldt or Peruvian 
Current and distributed along the Pacific coasts. It is also possible 
that such drift might ultimately be carried past the Galapagos 
Islands into the stream of the South Equatorial Current and in this 
manner be returned to the north-east coasts of Australia. But 
since at least six years would be taken up in the double traverse 
from New Zealand to South America and back to Australia, it is 
for several reasons doubtful whether as far as seeds are concerned 
it would be of any effective value. 

One must not ignore the possibility of seed-drift being carried 
round the Horn from the west to the east side of Tierra del Fuego. 
Not all of that part of the great " west wind drift current " which 
strikes the west coast of South America south of the 37th parallel 
is deflected north in the Peruvian Current. It gives rise south of 
the 50th parallel to a small stream that doubling Cape Horn joins 
the Antarctic Current, which proceeding northward meets the 
Brazilian Current off the estuary of the Plate. Schott lays down 
the track in Map 6 of a bottle which, after being dropped overboard 
off the west coast of Fuegia in about lat. 54° S. was recovered in 
the Falkland Islands (see p. 22 of his text). 

The probability of tropical South America supplying tropical 
North-east Australia with littoral plants through the agency of 
the South Equatorial Current will be subsequently discussed. On 
its eastern tropical coasts South America would receive drift from 
tropical West Africa through the Main Equatorial Current, as ex- 
plained in Chapter III. ; whilst the South Atlantic Connecting Current 
would carry materials from its extra-tropical eastern shores to South 
Africa. The fact that drift can double the Horn in the Antarctic 
Current and be transferred from the west coasts of Fuegia to the 
eastern side of the continent is noticed in the same chapter. But 
it is as a distributor of drift to Southern Australia, Northern New 
Zealand, the islands to the north of Kerguelen, and occasionally 
to South Africa that Fuegia plays the most important role. 

Africa and its Current-Connections. — The last of these 
southern continental land-masses to be here dealt with is Africa. 



CURRENT-CONNECTIONS IN S. HEMISPHERE 301 

Its opposite shores display the same reciprocity in the exchange 
of drift that is exhibited t>y South America. Whilst on the west 
the tropical borders would distribute drift to the New World through 
the agencies of the equatorial currents, those on the east would be 
the recipients of drift from tropical North-west Australia and from 
Malaya. So also the western extra-tropical coasts would receive 
drift from high latitudes in South America, and the corresponding 
eastern coasts would distribute it to the southern borders of Australia. 

The part taken by the equatorial currents of the Atlantic in trans- 
porting drift to America is dealt with elsewhere (Chapter III.). We 
are here principally concerned with the materials transported from 
the Gulf of Guinea to the coast of Brazil by the Main Equatorial 
Current, the time occupied in the passage being only three months. 
The western shores of South Africa would receive drift from extra- 
tropical South America that had been brought within the influence 
of the South Atlantic Connecting Current by the Brazilian Stream 
from the north and by the Antarctic Current from the Horn. The 
course taken would be that followed by a bottle dropped overboard 
in the middle of the South Atlantic in about lat. 42° S. and long. 
32° W., which was stranded near the Cape of Good Hope (Schott, 
Table 4, No. 97). The indications of bottle-drift data are that drift 
could not be carried direct from the tropics of the New W T orld to 
those of West Africa in the Counter Equatorial Current, except 
under exceptional circumstances (Chapter III.). 

To the eastern coasts of Africa, from the equator southward, 
tropical drift would be brought across the Indian Ocean by the 
South Equatorial Current from Malaya and North-west Australia; 
and its destination on the African coast would depend on whether 
it took the direct course north of Madagascar, or passed south to 
get within the influence of the Mozambique and Agulhas Current. 
It is also highly probable that the West Australian Current, which 
represents the northern offshoot of the West Wind Drift Current 
of the Roaring Forties, would after striking the south-west corner 
of Australia carry with it not only West Australian drift-materials, 
but also South African drift, which, brought by it within the influence 
of the South Equatorial Current, would be ultimately returned to 
the continent from which it hailed. It is even possible that Fuegian 
drift may be carried into the West Australian Current and thence 
into the Equatorial Current, finally reaching tropical East Africa 
in the company of South African, Australian, and Malayan drift. 
During its traverse of the Indian Ocean this equatorial stream would 
deposit samples of its gatherings from four continents on Keeling 
Atoll, the Chagos Islands, the Seychelles, the Mascarene Islands, 
and Madagascar. 

Let us look a little more closely into the play of the currents in 
the Indian Ocean from the equator southward, as exemplified by the 
tale of the drifting bottle. It is suggestively illustrated in Schott's 
maps and in his text; and by adding a few other data we shall 
obtain a fair representation of the work of the currents in distributing 
drift in these seas. However, to quote from the American bottle- 
drift charts for the North Atlantic, " it should be noted that the in- 



302 PLANTS, SEEDS, AND CURRENTS 



dividual drifts as laid down upon the chart, do not necessarily represent 
the actual surface currents of the ocean, but the resultant effect of 
all the forces to which the bottle was exposed during its drift." 

The bottle-drifts of the Indian Ocean are grouped by Schott into 
(a) those of the region of the monsoon currents, that is, north of 
5°-10° S. lat. ; (b) those of the belt of the 1 South-east Trade between 
10° and 30° S. ; (c) and those of the region of the Roaring Forties 
or " braven Westwinde." It would appear from his chart and his 
remarks (pp. 20-22) that the northern part of the Malayan region 
is more likely to receive drift from the westward than to distribute 
it in that direction. Thus we should expect to find drift on the 
beaches of the west side of Sumatra and of the Malay Peninsula 
from Southern India and Ceylon and from the shores of the Arabian 
Sea. On the other hand, the bottle-drift data also indicate that 
drift may at times be carried from the west coast of Sumatra to the 
Maldives and even to the shores of Equatorial Africa. This direct 
communication between North-west Malaya and the African east 
coast under the equator is exemplified by a bottle thrown over in 
about lat. 2° N. some 400 miles west of Sumatra, which was recovered 
160 days afterwards under the equator on the East African coast, 
having crossed the Indian Ocean at a minimum rate of 18-7 miles 
a day, the distance covered being about 3000 miles (Schott, p. 21, 
quoted from the American Pilot Chart for June 1895). 

In the case of Southern Malaya, meaning thereby the islands east 
of Java that face Australia, there would be a regular supply of drift 
to the East African coasts through the South Equatorial or South- 
east Trade Current. This is illustrated in part by the track of a 
bottle which was cast over about mid-way between the island of 
Sumbawa and North-west Australia in about 15° S. and long. 116° E. 
and was recovered in the Chagos Islands (Schott, Table 5, No. 23). 
Its track represents the first half of the passage taken by drift in 
crossing the Indian Ocean from the seas between the Malayan 
Islands and North-west Australia. The course followed by the 
bottle lies close to Keeling Atoll, and thus enables us to appeal to 
a witness who particularly interested himself in these matters during 
his sojourn in this part of the world, viz. Mr. Wood- Jones. As a 
spectator of the actual start in these Malayo-Australian waters of 
Malayan drift on its passage across the Indian Ocean to Equatorial 
Africa he thus writes in his Coral and Atolls (p. 295) : " During a 
stay of a fortnight in October 1906, in a ship lying on cable ground 
some twenty miles south of Sumbawa, the current flowed constantly 
westward at the rate of about one and a half knots ; and the waters 
were carrying all sorts of drift wrack in their stream." 

But Wood- Jones aids us still further in this matter. By adding 
experiment to observation he enables us to complete the traverse 
across the Indian Ocean which was performed in part by the bottle 
above alluded to. He had especially in his mind the subject of the 
transport in the South-east Trade Current of Malayan drift, whether 
plant or animal, to Keeling Atoll; and, as already indicated, the 
track of thebottlecast over be ween Sumbawa and North-west Australia 
is laid down by Schott as passing close to Keeling Atoll on the way 



CURRENT-CONNECTIONS IN S. HEMISPHERE 303 



to the Chagos Islands. It was from this atoll that Wood-Jones 
made numerous experiments with bottles, the results of which are 
specially important in this connection. Although only two were 
recovered, both were found on " exactly the same spot " at a place 
called Ras Day at Brava (1° 6' N; 44° 2' E.) in Italian Somaliland. 
Both of them, strange to relate, were dispatched on the same day, 
November 15, 1905, and in both cases the record was returned by 
the same person, Captain Piazza, Resident of Brava. The first 
was found on May 27, 1906, an interval of 193 days, which gives a 
daily drift of not less than seventeen miles over a distance of about 
3300 miles. The second was not recovered until July 11, 1907, 
the cause of the great delay being not explained. Wood-Jones 
(p. 295) considers that drift would require from forty to sixty days to 
reach Keeling Atoll from the Malayan Islands to the eastward. 
By piecing the data together we may assume that the whole traverse 
from south of Sumbawa to Equatorial Africa would be accomplished 
in not more than eight months, the distance being about 4500 miles. 

As an agent in carrying drift from tropical Africa to Malaya the 
Indian Counter Current, which courses eastward along equatorial 
latitudes, seems to be ineffective. It is scarcely illustrated in Schott's 
maps, and, as in the Atlantic and Pacific Oceans, we may be permitted 
to doubt whether any purely compensating current could, except 
on very rare occasions, transport drift across an ocean. In the case 
of this particular counter- current floating materials would be driven 
out of its influence, southward during the north-east monsoon and 
northward in the south-west monsoon. 

Summing up the effective current-connections between Africa and 
Malaya, as far as they are reflected in bottle-drift, we may infer that 
Malaya is the giver and Africa the recipient. But it would seem that 
whether it came from Sumatra or from the islands east of Java, 
Malayan drift reaching East Africa would be mostly gathered under 
the equator. This was the opinion also formed by Wood-Jones 
when he reflected on the two facts (a) that crocodiles and large 
snakes have been stranded alive amongst the Malayan vegetable 
drift that is regularly floated to Keeling Atoll, and (b) that bottles 
thrown into the sea by him from this atoll had been stranded at 
Brava on the coast of Equatorial Africa. " I would dearly love " 
(he writes on p. 294) " to examine the coast-line of Italian Somaliland 
in the region of Ras Day (Brava) to see if there was not some waif 
that had succeeded in making a new home there, and that could 
clearly tell of a Malayan or an Australian origin. I do not doubt 
that some such colonist would certainly be found — some typical 
Asiatic or Australian intruder on the African fauna and flora." 

In the westerly traverse of the Indian Ocean in equatorial latitudes 
by Malayan drift much would depend on the season of the year. 
The bottles dispatched from Keeling Atoll by Wood-Jones in Novem- 
ber were impelled westward during the period of the north-east 
monsoon which probably came to their assistance when the South- 
east Trade failed. Had they been sent off in May, they would, 
when near the Line in mid-ocean, have been diverted north towards 
India, and when the south-west monsoon gave place a few months 



304 



PLANTS, SEEDS, AND CURRENTS 



later to the north-east monsoon they would have been carried to 
the south-west, and might have been the sport of the currents for 
years. This seems to have been the fate of a bottle cast over in 
May in lat. 6° S. to the south-east of the Seychelles, which was 
recovered two and a quarter years after in the Chagos Islands, 800 
miles to the eastward (Schott, p. 21, Map 5, No. 8). So again the 
bottle before mentioned which was found on the shores of Equatorial 
Africa 160 days after it had been dropped into the sea in 2° N. lat., 
some 400 miles west of Sumatra, began its passage in January, that 
is, in the height of the north-east monsoon. Had it started in July 
during the height of the south-west monsoon, it would have been 
carried back to Northern Sumatra or the Malay Peninsula, as is 
well brought out in Schott' s map in the case of other bottles. 

The general effect of the alternating influence of the surface drift 
currents set up in the equatorial waters of the Indian Ocean by the 
monsoons would be to restrict the arrival on the coasts of Equatorial 
Africa of drift from Malaya and North-west Australia to the half 
of the year corresponding to the period of the north-east monsoon. 
In the other half of the year, if it did not become the sport of the 
currents between Ceylon and Madagascar, it might be stranded 
almost anywhere on the shores of the northern half of the Indian 
Ocean. 

This leads us to consider the current- connections of the east side 
of Africa with Western Australia, and in so doing we shall be compelled 
to cover old ground. Here the South Equatorial Current, or the 
South-east Trade Drift, is the direct transporting agency, and Africa 
thus figures as the recipient. The track that seeds from the tropical 
coasts of North-west Australia would take is indicated (a) by the 
bottle, already alluded to, that after being dropped into the sea 
about half-way between Sumbawa and the opposite Australian shores 
passed close to Keeling Atoll and was stranded on the Chagos Islands, 
(b) by the two bottles before mentioned that were carried from 
Keeling Atoll to Brava on the African coast in 1° N. lat. Such 
seed-drift would presumably, therefore, reach Equatorial Africa. 
It would be derived from the adjacent coasts of North-west Australia 
and Malaya and from the shores of the Arafura Sea. 

But drift from Western Australia in the vicinity of and to the 
south of the North-west Cape would also come within the influence 
of the South-east Trade Current. With the same northerly slant 
that is exhibited in the track of the drift from the Timor and Arafura 
Seas, it would arrive at a point in mid-ocean — about the 15th parallel 
of south latitude and the 75th meridian of east longitude — where 
it would have to choose between a course lying north of Madagascar 
bringing it to the vicinity of Zanzibar, and a course south of Madagascar 
bringing it into the Natal Current and resulting in most cases in its 
being stranded on the shores of Cape Colony. The probable deter- 
mining cause would lie in the indirect influence of the monsoons 
some degrees further north, the northern course being taken during 
the south-west monsoon and the southern course in the north-east 
monsoon. 

The sequence of events is clearly shown in No. 5 of Schott's charts. 



CURRENT-CONNECTIONS IN S. HEMISPHERE 305 



A bottle (No. 37) , which was dropped over in about lat. 16° S. and 
long. 98° E., nearly 1000 miles north-west of the North-west Cape 
of Australia, was recovered on the south-east side of Madagascar. 
Presumably it represents the course taken by drift from the vicinity 
of this corner of Australia. After a drift westward of about 1100 
miles, it crossed in about lat. 15° S. and near the 80th meridian 
of east longitude the starting-place of two bottles (18 and 38 of 
Schott's Chart 5, and mentioned on p. 22) only 120 miles east and 
west of each other, one of which was stranded on the African coast 
immediately north of Zanzibar, whilst the other was thrown up on 
the south-east shores of Madagascar. Schott lays down the tracks 
of bottles from the southern end of Madagascar and its vicinity, 
which, after getting into the Natal Current, were beached on the 
south coast of Cape Colony east of Cape Agulhas. We thus perceive 
how seed-drift from Western Australia may be distributed on the 
East Coast of Africa from Zanzibar to the southern extreme of the 
continent. 

But as regards Australia, Africa may be a giver as well as a re- 
ceiver. Drift from the southern extreme may be carried by the 
Agulhas Current into the West Wind Drift Current and thus to the 
south coasts of Australia. Of this a suggestive example is afforded 
by a bottle, thrown overboard about seventy miles south-east of 
Cape Agulhas, which was stranded on the shores of the Great Aus- 
tralian Bight (Schott, Map 5, No. 31). However, the Agulhas 
Current has a subsidiary branch that doubles the Cape, and as 
indicated by the bottle-drift data (see p. 63), may bear drift from 
the shores of Natal and from the south-east coasts of Cape Colony 
to the African West Coasts. Though the event is probably infrequent, 
seeds could be transferred in this way from the east to the west 
side of the continent. It is even possible that drift from Western 
Australia, after traversing the Indian Ocean to the south of Mada- 
gascar might in this manner reach the South-west Coast of Africa. 

It is likely that drift in its passage from South Africa towards 
Australia may at times perform the circuit of the Indian Ocean. 
South African drift, after crossing the ocean in the West Wind 
Current, may be carried north in the West Australian branch of 
the current into the South-east Trade belt, and thence across the 
ocean to Africa, thus completing the circuit of the Indian Ocean. 
Wood-Jones (p. 295) refers to a bottle " launched in Mauritius " that 
is said to have reached Keeling Atoll. No other data are given; 
but he is quite justified in assuming that it " almost certainly came 
to the atoll from the eastward, after completing an enormous circuit 
of the Indian Ocean." This bottle would have followed the track,, 
above indicated, to the south of Madagascar and towards the southern 
extreme of Africa, subsequently crossing the Indian Ocean in the 
belt of the Roaring Forties, and turning north in the West Australian 
Current to meet the South Equatorial Current (South-east Trade 
Drift) that flows past Keeling Atoll. It would have accomplished 
about 10,000 miles in about three years. 

The Influence of the Current- Connections in the Southern 
Hemisphere on the Distribution of Littoral and Estuarine 
x 



306 PLANTS, SEEDS, AND CURRENTS 



Plants. — Seed- drift travels west in tropical latitudes and east in 
temperate latitudes, from which it follows that whilst in the temperate 
latitudes of the southern hemisphere we look to the west for the 
source of the littoral and estuarine plants that are dispersed by- 
currents, in the tropics we look to the east. On account of the 
usual slant of the trans-oceanic traverses of the drifting bottles 
there is, however, generally a marked shifting of the latitude either 
to the north or to the south. But, apart from this, the general 
effect would be that in the tropics we should look for West African 
affinities on the eastern shores of South America, for South American 
affinities on the coasts of Malaya and Australia, and for Malayan 
and Australian affinities in East Africa. So also in temperate 
latitudes we should look for South American relations in South 
Africa, Australia, and New Zealand; for South African affinities 
in Australia ; and for Australian and New Zealand relations in South 
America. 

Although the general principle, just enunciated, still applies, 
some important modifications are necessitated on account of the 
usual northward and southward slant of the currents, as evidenced 
by bottle- drift. Except within the narrow limits of the equatorial 
Atlantic the shifting in the latitude generally amounts to several 
degrees. We have seen that Fuegian drift when it reaches Australia 
has diminished its latitude by about twenty degrees. On the other 
hand, New Zealand drift when crossing the Pacific to South America 
is deflected only four or five degrees to the north. Bottles from off 
the equatorial coasts of South America would strike the shores of 
North-east Australia a dozen degrees farther south. This southerly 
slant of drift in the South Equatorial Current is continued right 
cross the Pacific, and may be even greater than is just indicated. A 
bottle thrown into the sea on the 10th parallel of south latitude in 
the meridian of the Galapagos Islands would be stranded on the 
east coast of Australia on about the 30th parallel of latitude. The 
effect of this slant, as already shown, is the throwing back of East 
Australian drift on the shores of that island continent, so that 
Australia is in this manner unable to contribute drift to South 
America. The only drift that could reach South America from these 
longitudes would be from higher latitudes, namely, from the southern 
end of New Zealand and the Antarctic islands to the southward. 

In the southern tropics of the Indian Ocean drift carried along 
in the South-east Trade or South Equatorial Current is inclined 
to the north, so that bottles dropped into the sea about the 
16th parallel of south latitude between Java and North-west Australia 
would be beached on the East African coast under the equator. 
It is remarkable, as shown by the tracks of bottles laid down in 
Schott's Chart 5, that drift from the southern extreme of Africa, 
which is carried by the Agulhas Current into the West Wind Current, 
is transported across the Indian Ocean without much change of 
latitude, being ultimately thrown up on the south coasts of Australia. 

In applying, therefore, to the southern hemisphere the principle 
that in the case of littoral and other plants dispersed by currents we 
should in temperate latitudes look to the west for their source and 



CURRENT-CONNECTIONS IN S. HEMISPHERE 307 



in the tropics look to the east, we have often to make a correction 
for change in latitude. The problem, when re-stated, would be as 
follows. In the tropics of the Pacific we should expect to find plants 
of Equatorial South America in Melanesia and North-east Australia ; 
in those of the Indian Ocean plants of Malaya and North-west 
Australia on the equatorial coasts of East Africa; and in those 
of the Atlantic, West African plants on the shores of Brazil and of 
the Guianas. In the temperate latitudes we should look for Fuegian 
plants in Cape Colony, Southern Australia, and the northern end of 
New Zealand ; for South African plants in Southern Australia ; and 
for plants of the south part of New Zealand in South Chile. We should 
not look for Australian littoral plants in South America. We will 
now deal more in detail with these matters : — 

(A) As illustrated in Temperate Latitudes. — When the same littoral 
plants occur in the cooler latitudes of two of these southern land- 
masses we are guided by the currents in determining which of the 
two is the source. Thus, there are two littoral plants, Sophora 
tetraptera and Convolvulus soldanella, which occur alike in New 
Zealand and South Chile. This singular distribution is one of the 
mysteries of the Southern Ocean. Both of them possess buoyant 
seeds capable of dispersal over an ocean by the currents. Thus, 
according to my experiments on the seeds of Sophora tetraptera, 
which I gathered on the Chilian coast, half of them remained afloat 
after seven months in sea-water and retained their germinative 
capacity. From results for the seeds of Convolvulus soldanella, which 
are given in my book on Plant Dispersal (p. 542), it appears that 30 
per cent, remained afloat after eighteen months in sea- water and 
subsequently germinated when sown out. Both of these plants 
are confined to the west side of temperate South America. Since 
they occur in latitudes north of 42° S. (Ibid., pp. 476-9) they would 
come within the influence of the northward flowing Peruvian Current 
and would have no opportunity of doubling Cape Horn. They are 
found just in those South Chilian latitudes which, as before remarked, 
would receive New Zealand drift; and we can have no hesitation 
in regarding them as introduced into South America from New 
Zealand by the currents. (Both of these plants are treated in detail 
in my book on Plant Dispersal. The experiments on S. tetraptera 
were continued after the publication of the earlier work.) 

Yet on the part of Sophora tetraptera there has been an effort to 
recross the Pacific in warmer latitudes. Not only does it grow in 
the Juan Fernandez Islands, whither the seeds were probably brought 
from the southward by the Peruvian Current, but it has been found 
on Easter Island (lat. 27° S.) in the open ocean. In this last case 
it would seem that the seeds, after being carried north in the Peruvian 
Current, came within the influence of the South Equatorial Current. 
It is not a plant of the tropics, and Easter Island seems to be the 
northerly limit of its effective dispersal by currents. 

The data indicate the little likelihood of seeds from the temperate 
or extra-tropical western shores of South America being able to 
arrive in similar latitudes on the Australian side of the Pacific in an 
effective condition. Even if the current-connections permitted the 



308 PLANTS, SEEDS, AND CURRENTS 



transport, it is doubtful whether either the seeds of Convolvulus 
soldanella or those of Sophora tetraptera would be able to withstand 
the three-and-a-half years' immersion in sea-water that would be 
involved in the passage. Effective dispersal of temperate shore 
plants by the currents in the Southern Ocean could only be brought 
about by the easterly drift in the latitudes of the Roaring Forties. 
Very instructive is the caution given to mariners in the Admiralty 
chart of the west coast of South America (No. 786). It warns the 
navigator against an easterly current setting directly on the coast 
between the latitudes of 37° and 50° S. At the southern limit, as 
we have seen, would be stranded drift from the seas around Kerguelen 
and from the islands south of New Zealand. Towards the northern 
imit would be found drift from the southern part of New Zealand. 

(B) As illustrated in Tropical Latitudes. — As I have observed in my 
previous work, dispersal by currents in tropical seas is a far more 
effective agency than in temperate regions. The westerly set of 
the equatorial currents is responsible for much that is held in common 
among the rank and luxuriant vegetation of coasts and estuaries 
in warm latitudes. The principle of looking to the east has an 
important application when we are concerned with the existence 
of practically the same littoral and estuarine flora on the opposite 
sides of the same ocean, as in the cases of the Atlantic and Indian 
Oceans. Thus, in the tropical Atlantic we should speak, not of 
American plants in West Africa, but of West African plants in 
America. So again in the Indian Ocean it is tropical East Africa that 
derives its littoral flora from Malaya and North-west Australia. 
It would be incorrect to speak of East African plants in Malaya. 
The position adopted by Mr. Wood-Jones as regards the dispersal 
by currents of tropical plants in the Indian Ocean has been already 
stated. His bottle-drift experiments led him to look for Malayan 
and Australian intruders in the African flora, or, in other words, 
to look to the east and not to the west in order to explain the influence 
of the currents on distribution. 

In the case of the Pacific it would be useless, for reasons before 
given, to seek for tropical Australian plants on the west coast of 
equatorial South America. Whatever similarities exist in the 
littoral floras of these two regions would result from the transport 
of seeds of South American plants westward across the ocean in the 
South Equatorial Current. On account, however, of the great 
breadth of the Pacific Ocean and the numerous perils to which the 
floating seed would be exposed in an ocean traverse of from 7000 
to 8000 miles, the Asiatic littoral plants hold the field in tropical 
Australia. If we exclude the cosmopolitan beach and estuarine 
plants, such as Ipomoea pes-caprce and Entada scandens, that occur 
round the tropical zone, it is only occasionally, as with the American 
species of Rhizophora (Rh. mangle) in Fiji, that we can find direct 
evidence of the extension westward across the Pacific of the estuarine 
and coast plants of the west side of equatorial South America. 
Island groups in the track of the currents, that would be adapted 
to serve as stepping-stones for the westward extension of the South 
American mangrove flora, are few. 



CURRENT-CONNECTIONS IN S. HEMISPHERE 309 



Tropical littoral plants, both strand and estuarine, divide the 
warm latitudes of the globe into two great regions, the New World 
region including both sides of America and also West Africa, and 
the Old World region excluding West Africa and including Poly- 
nesia. Whilst several beach plants range through both regions, 
more are restricted to only one. Amongst the mangroves and 
their associates, the genera Rhizophora, Avicennia and Carapa 
occur in both regions, but represented by different species; whilst 
Brugiera and Lumnitzera are confined to that of the Old World 
and Laguncularia to that of the New World. The contrast between 
the two regions is best shown in the mangrove flora, and nowhere 
is this better displayed than on the opposite sides of tropical Africa, 
all the plants concerned being known to be dispersed by currents. 

Looking at the current- connections between Australia and New 
Zealand on the one side and South America on the other, we may 
infer that whereas New Zealand in its relation with South America 
appears both as a giver and a recipient, Australia would receive 
South American plants but could make no return. In New Zealand 
there is a singular reciprocal relation, the northern island receiving 
littoral plants from Fuegia and the southern island returning shore 
plants to South America, some nine or ten degrees north of the 
Straits of Magellan. It is remarkable that concerning the general 
relations of the faunas and floras of these ocean-parted regions of 
the southern hemisphere Mr. Hedley arrives at a very similar con- 
clusion in his discussion of " the community of austral life " given in his 
paper on the palaeographic relations of Antarctica (Proc. Linn. Soc. 
Lond., June 1912, p. 88), the chief point of difference being that he 
considers the transference to have taken place by way of the Ant- 
arctic continent. " Whereas New Zealand " (thus he writes) " in its 
relation with South America, via Antarctica, appears both as a giver 
and a receiver, Australia, on the contrary, seems to have made no 
return to South America, but to have received all and given nothing." 
It is not without significance that if the questions of the relations 
between the faunas and floras of these ocean-parted regions had 
been entirely one of currents, Mr. Hedley could not have employed 
different language. 

One may conclude this chapter with the remark that as far as 
the currents are concerned many of the same principles would 
apply, with limitations, to the northern hemisphere. Thus we 
have in the north the same rule, with the same implications, that 
drift travels east in temperate and west in tropical latitudes. This 
is abundantly illustrated for the North Atlantic in Chapters III 
and IV, and it would also be true of the North Pacific Ocean. 

Summary 

1. The matter of the current- connections of the southern hemi- 
sphere is dealt with here only in so far as it can throw light on the 
dispersal of seeds in the Southern Ocean, and the operations of 
the currents are discussed only in so far as they are reflected in the 
track of the drifting bottle, itself " the resultant effect of all the 



310 PLANTS, SEEDS, AND CURRENTS 



forces to which the bottle was exposed during its drift." Even in 
this respect the field of inquiry is restricted, since it is chiefly littoral 
and estuarine plants that are distributed by currents. 

2. The author at first refers to one of the most interesting of these 
phenomena, namely, the drifting of bottles and wreckage round 
the greater part of the globe before the westerly winds in relatively 
high latitudes. However, since the easterly drift across the Southern 
Ocean displays a continuous northerly slant, the circuit could not 
be accomplished by the same bottle unless it started some distance 
to the south of the Horn, that is, beyond the 60th parallel as from 
the South Shetland Islands. Fuegian drift would be largely inter- 
cepted by Australia, Tasmania, and the northern part of New Zealand ; 
whilst the tailings that slipped past the North Cape would be thrown 
back on the Queensland coasts through the westerly set of the 
currents. Drift from the southern extreme of New Zealand would 
be stranded on the shores of South Chile, and only drift from the 
southernmost of the Antarctic islands would be likely to clear the 
Horn. The uninterrupted circuit of the globe in these high latitudes 
would take up rather over three years (pp. 294-6). 

3. The current-connections of the great land-masses of the south 
are then separately dealt with, and Australia is first discussed. 
Whilst from its tropical north-west shores it would distribute drift 
across the Indian Ocean to the coasts of tropical East Africa and from 
its extra-tropical western shores to Cape Colony, it would receive 
along the whole length of its southern coasts drift from Fuegia and 
the intervening islands of the Southern Ocean, as well as from South 
Africa. From its south-eastern coasts it would supply materials 
to the north end of New Zealand ; whilst on its middle-east and north- 
east coasts would be stranded drift from the islands of the tropical 
South Pacific and from equatorial South America. The only materials 
it would receive from New Zealand would be derived from the vicinity 
of the North Cape : through the westerly set of the currents between 
that headland and Fiji they would be carried to the Queensland 
coasts, and the same currents would effectively block the passage 
of Australian drift across the Pacific (pp. 297-8). 

4. In the case of New Zealand a curious reciprocal relation is 
noticed. Whilst its northern end would receive drift from Tasmania, 
from the south coasts of Australia, and tailings from Fuegia and the 
intervening islands of the Southern Ocean north of Kerguelen, its 
southern end would distribute drift to South Chile. Drift from the 
vicinity of the North Cape would be carried back to the coasts of 
Queensland; whilst its south-west coasts would receive drift from 
Kerguelen and the islands south of it, as well as from the distant 
South Orkney and South Shetland Islands and from the shores of 
the Antarctic continent adjacent to them (p. 299). 

5. South America is then dealt with. Whilst, as above explained, 
it could receive nothing from Australia, there would be stranded on 
its shores south of the 40th parallel drift from the south end of New 
Zealand as well as from the islands in the higher latitudes to the 
westward as named in the preceding paragraph. Drift from its 
equatorial Pacific coasts would reach North-west Australia through 



CURRENT- CONNECTIONS IN S. HEMISPHERE 311 



the agency of the South Equatorial Current. To its tropical Atlantic 
coasts the Main Equatorial Current would bring drift from tropical 
West Africa ; whilst in the stream of the South Atlantic Connecting 
Current would be carried materials from its extra-tropical shores to 
South Africa (pp. 299-300). 

6. With regard to Africa it is shown that its opposite coasts 
display the same reciprocity in the exchange of drift that is exhibited 
by South America. Whilst the tropical borders on the west would 
distribute drift to the New World through the agencies of the equa- 
torial currents, those on the east would be the recipients of drift 
from tropical North-west Australia and from Malaya. So also the 
western extra-tropical coasts would receive drift from high latitudes 
in South America, and the corresponding eastern coasts would supply 
it to the southern borders of Australia. The connections across the 
Indian Ocean with Malaya and Australia are then discussed. In 
the first case it is shown that Malaya is the giver and Africa the 
recipient, the drift being transported in the South-east Trade Current 
to equatorial East Africa. The general effect of the alternating 
influence of the monsoons would be to restrict the arrival of Malayan 
drift to the period of the north-east monsoon. In the other half of 
the year it might be stranded almost anywhere on the shores of the 
northern half of the Indian Ocean. As regards Australia, it is shown 
that whilst drift from its north-west shores would reach tropical 
East Africa, drift from its extra-tropical western coasts might reach 
Cape Colony. But as concerns Australia, Africa may be the giver 
as well as the receiver, since South African drift may arrive on the 
south coasts of Australia by the way of the Agulhas and West Wind 
Drift Currents (pp. 300-305). 

7. In applying these principles to the distribution of littoral and 
estuarine plants in the southern hemisphere it is observed that 
seed-drift travels west in tropical latitudes and east in temperate 
latitudes. Whilst in the temperate zone we look to the west for 
the source of plants that are dispersed by currents, in the tropics 
we look to the east. In the tropics we look for South American 
plants in North-east Australia, for Malayan and Australian plants 
in East Africa, and for West African plants on the shores of 
Brazil and of the Guianas. In the temperate zone we look for 
Fuegian plants in South Africa, Southern Australia, and the 
northern end of New Zealand; for South African plants in 
Southern Australia; and for plants of southern New Zealand in 
South Chile. Though there is often a marked change in latitude, 
the rule holds good that for the source of the elements common 
to littoral and estuarine floras on both sides of an ocean we must, 
as far as the agency of the current is concerned, look to the east 
in the tropics and to the west in the temperate zone (p. 306). 

8. In illustration of these principles in the temperate zone the 
instances of Convolvulus soldanella and Sophora tetraptera are taken. 
In the tropics, it is shown that whilst in the Indian and Atlantic 
Oceans the littoral and estuarine floras on the opposite sides are 
closely similar, the fusion has been retarded in the Pacific on account 
of the great width of the ocean and the paucity of suitable stepping- 



312 PLANTS, SEEDS, AND CURRENTS 



stones in the form of islands that would support a mangrove flora 
(pp. 307-309). 

9. The inference that New Zealand in its relation with South America 
iigures both as giver and receiver, whilst Australia merely receives 
South American plants and makes no return, though here concerned 
only with coastal plants, is the identical conclusion framed by Mr. 
Hedley with respect to the general relations between the faunas and 
.floras of these ocean-parted lands (p. 309). 



LIST OF THE PRINCIPAL WORKS QUOTED 

GfuPPY, H. B., Observations of a Naturalist in the Pacific, Vol. II., Plant-Dispersal, 
1906. 

Hedley, C, The Palseographical Relations of Antarctica, Proc. Linn. Soc. 
London, 1911-12. 

Page, J., on the bottle-drift observations of the U.S.A. Hydrographic Office, 
National Geographic Magazine, Vol. XH., 1901, New York. 

Russell, H. C, Current papers in Journ. Roy. Soc. N.S.W., 1894 and 1896. (Quoted 
in these pages from Schott's memoir.) 

Schott, G., Die Flaschenposten der Deutschen Seewarte, Archiv der Deutschen 
Seewarte, XX., 1897. 

Wood-Jones, F., Coral and Atolls, 1910, p. 294. 



CHAPTER XIV 



DIFFERENTIATION 

The author approached the study of plant-distribution through 
his investigations into the agencies of dispersal, the results of which 
are given in his book on Plant Dispersal. At first inclined to attach 
undue importance to these agencies, the effect of his special inquiries 
concerning littoral plants and insular floras, he came to learn that, 
however efficacious they might be in stocking islands with their 
plants, they acquired a diminished significance in continental regions. 
We are there brought face to face with problems concerned with 
past changes in the history of climate, with the relations of land and 
sea in the lapsed geological ages, and with those mysterious revolu- 
tions in plant-forms that have affected the whole world. It was the 
behaviour of the polymorphous or highly variable species in the 
Pacific islands, differentiating as it does in every group, that first 
drew his attention towards the real meaning of distribution, a matter 
discussed in the work above named. 

The Differentiation Theory and its Limitations. — The view 
that the history of our globe, as far as secondary causes are in opera- 
tion, is essentially the history of the differentiation of primitive 
world-ranging generalised types in response to the differentiation of 
their conditions, is far from being a novel one. It has been indepen- 
dently acquired by a number of investigators; and, indeed, many 
lines of inquiry affecting the great groups of animals as well as plants 
converge towards this conclusion. It does not, however, attempt to 
explain the origin of types, nor does it account for evolutionary 
progress, processes which are considered to be under the sway of 
other influences that are not at present within our field of cognition. 
It is concerned only with the response of organisms to the demands 
of their environment, and all that seems purposive in the animal and 
plant worlds, all that is bound up with the great scheme of progres- 
sive evolution, is viewed much as the old naturalists were wont to 
regard it. 

The Author's Association with the Theory. — In the last 
chapter of his Plant Dispersal, which was published in 1906, the 
theory is referred to in different connections. Thus the loss of the 
viviparous habit, that is assumed to have been characteristic of 
primitive plants under uniform climatic conditions, and the conse- 
quent development of the rest-period of the seed, are ascribed to 
the differentiation of climate and to the resulting seasonal variation. 
But attention is especially paid to the concurrent differentiation of 

313 



314 PLANTS, SEEDS, AND CURRENTS 



climate, bird, and plant, the range of the bird being largely controlled 
by the climate, and the range of the plant being mainly dependent 
on the bird. In all cases there was the conception of a primal 
world, where uniformity of conditions prevailed, and of primitive 
generalised types that in their differentiation responded through the 
ages to the diversification of their conditions. These views were 
considerably extended in a paper on " Plant-Distribution from an 
Old Standpoint," read before the Victoria Institute of London in 
April 1907, when it was contended that the differentiation theory 
presents us with a good working hypothesis for the age of the flower- 
ing plants. They were further emphasised and enlarged in a paper 
on " The Distribution of Plants and Animals " in Petermann's 
Mitteilungen for 1910 (Heft II.). The paper was produced in a 
German translation by one of his staff through the courtesy of the 
editor ; and although printed in a somewhat abbreviated form there 
was no impairment of the general line of the argument. 

But in all these statements of his views the author failed to recog- 
nise that although the differentiation theory explained the diversity 
of forms, there was much in distribution that it did not of itself 
account for. What was lacking was the proper appreciation of the 
part played by the arrangement of the continents in determining 
during secular variations of climate plant- distribution. The de- 
ficiency he has endeavoured here to supply; and whilst devoting 
this chapter to the discussion of the differentiation theory, he will 
deal with distribution as an expression of the geographical and 
climatic conditions just mentioned in the chapter succeeding it. 

Statement of the Theory. — Natural families, as at present 
recognised, seem to fall into two groups, the primitive and the 
derivative, the first world-ranging and the second restricted in their 
area. The primitive family as differentiation proceeds may give 
rise to (a) zonal families, as in the case of the two closely related 
families, the Primulacece of temperate latitudes and the Myrsinacece 
of the tropical zone; (b) continental families, where they are 
restricted to a continent, as in the cases of the Tropceolacece and 
Sarraceniacece to America; and regional families that are confined 
to a more circumscribed region, as in the case of the Goodeniacece to 
Australia and its vicinity. 

That differentiation and decrease of range go together is a prin- 
ciple that seems to prevail through the whole plant-world. It is 
seen in its last stages in the role of the polymorphous or highly 
variable species, which, whilst giving birth to varieties and local 
races in different parts of its range, still covers most of the area of 
the genus or sub-genus, as the case may be. It is seen even in the 
behaviour of the variety so produced ; and thus the process goes on 
until, as in Hawaii, different valleys and hill-tops may possess their 
own peculiar forms. But this is a subject that has been already 
discussed by the author in his work on the Pacific. Here he wishes 
to emphasise the point that the behaviour of a polymorphous species 
represents, though on a far smaller scale, the behaviour of the primi- 
tive generalised family types that once ranged the globe. The 
successive stages in the differentiation of a world-ranging family 



DIFFERENTIATION 



315 



type are regarded as a response to the stages in the differentiation 
of the conditions. 

Although there are still primitive families, like the Composite, the 
Cyperacece, etc., that occupy most of the globe, there are others 
where differentiation has proceeded so far that the original family 
type is lost. The lost type is then only represented in the characters 
that join together a number of families in a great plant-group, which, 
though they hold the world between them, respectively characterise 
different regions of it. There are several such alliances, and some 
are referred to in this connection in the author's Victoria Institute 
paper. Reference has already been made to the closely related 
families of the Primulacece and the Myrsinacece that between them 
range the globe, the first in the temperate regions and the second in 
the tropics. A similar example is offered by the Geranial alliance, 
of which the two oldest families, the Geraniacece and the Oxalidacece, 
divide the world between them, the first being most characteristic 
of the temperate zones and the last of the warmer regions of the 
globe. The great Scitamineous alliance illustrates the same prin- 
ciple in the warm regions of the world. Though there is no general- 
ised type now known, we find it represented in the characters common 
to the four closely connected families that range over warm lati- 
tudes : the Zingiber acece mainly in the Old World, the Cannacece and 
Marantacece mainly in America, and the Musacece fairly well shared 
between both hemispheres. 

But the recognition of this principle is not always easy, especially 
in those cases where, as in the Pandanacece, we have a family restricted 
to the tropics of the Old World with no very near relations in the 
New World. Though kindred families are not altogether wanting, 
it would be justifiable to presume that the families originally asso- 
ciated with it disappeared long since in the differentiating process. 
Where special influences have been at work rapidly disguising the 
characters of the primitive family, as in the case of the alliance of 
the insectivorous families, Sarraceniacece, Nepenthacece and Droseracece, 
it would seem that a wide gap must separate them from families of 
the same parentage that never acquired this habit. It would not 
appear that we could establish any direct connection between the 
cosmopolitan Droseracece as the mother family and the closely 
related American Sarraceniacece and Asiatic Nepenthacece as the 
offspring. 

In the family, in the tribe, in the genus, in the species, and in the 
variety and local race, we see the same principle at work; and to 
illustrate it we will draw nearly all our examples from the same 
plant-type. We see it in the fact that the Geraniacece which has 
given its name to an alliance of families, still holds most of the area 
of the primitive world-ranging type. We see it in the behaviour of 
the tribes within the family. Here the tribe Geranice, which comes 
nearest to the primitive form, has by far the greatest range, covering 
as it does nearly the entire area of the family. We see it in the 
genera of this tribe, where Geranium, the most primitive of all, the 
genus that lies farthest back in the line of descent, is the genus most 
widely distributed, occupying as it does nearly the range of the tribe. 



316 PLANTS, SEEDS, AND CURRENTS 



We see it again in the species within a genus ; but in a large genus 
like Geranium, which holds about 270 known species and has been 
subdivided by Knuth in his monograph in the Pflanzenreich series 
into thirty sections, we are restricted by the plan of that work to an 
appeal to the sections. Small genera are best suited to illustrate 
the principle, and in my book on the Pacific it is discussed in the case 
of Dodoncea, Metrosideros, and several others. However, its opera- 
tion within the sections of Geranium is often clearly exhibited. In 
such cases the parent species, or the type around which the other 
species group themselves, is highly variable, and has the largest 
range, covering the whole or the greater part of the area held by the 
section. 

Lastly, we see this principle at work within the limits of a species, 
and it is especially well exhibited in the varieties and local races of 
some of the species of Geranium. Thus, there are species which, 
whilst possessing a number of local varieties or races, have a parent 
form that includes within its range all the homes of the varieties and 
races. The behaviour of G. mexicanum, as indicated in Knuth's 
monograph, is very typical. It has the range of the section Mexicana, 
to which it belongs, all the other species of the section being confined 
to limited areas. It has a number of local forms, all of which group 
themselves around a variety that has the range of the species. 

Antiquity and Change. — There is not infrequently an obsession 
in these matters that time goes with change; and we are now and 
then apt to look upon some highly differentiated and rare plant- 
organism as far more ancient than some simple plant-type that 
abounds around us. This is a dangerous view to hold respecting 
family types, concerning which it can be contended with much better 
reason that the contrast is merely a matter of varying rates of differ- 
entiation. The scores of American genera of flowering plants that 
have remained unchanged since Cretaceous and early Tertiary times 
show clearly enough that antiquity by no means connotes change. 
The only valid explanation of the fact that in one continent a family 
may be more differentiated than in another, that is to say, that it 
is farther from the family type, is to be found in the more rapid 
operation of the process. 

Whilst we should expect to find a primitive family represented on 
all the larger continental tracts, the absence of some of the derivative 
families springing from the primitive type is often to be looked for. 
The differentiation theory takes the world as it is. If we find an 
explanation of the almost exclusive possession by South America of 
the Trop&olacea? (one of the Geranial alliance) in the relative isola- 
tion of that continent, it would surely be inconsistent to postulate, as 
Knuth does (p. 38), a connection between South America and South 
Africa in order to account for the occurrence of Geraniacea? in both 
continents. We must begin with the universal distribution of the 
primitive parent type of all the families of the alliance, and allow the 
extent of the differentiation to be determined by the arrangement 
of the land-masses and their internal conditions. The earlier stages 
of the process of change would be on similar lines, whilst the later 
changes would diverge widely. 



DIFFERENTIATION 



317 



The Australian Flora. — To illustrate the argument reference 
may be made to the Australian flora, where we find world-ranging 
families with a special Australian impress, such as the Leguminosce 
and the Proteacece, associated with families of later development and 
of purely Australian origin which represent, as in the Goodeniacece, a 
regional modification of a primitive widely distributed family type, 
the modification of which has been so extensive that the connections 
with the other descendants of the same family type in other parts 
of the world have been lost in the differentiation process. After I 
had elaborated this argument in some detail for this chapter I found 
that the whole matter had been treated on similar lines, but on a far 
more extensive scale, by Mr. E. C. Andrews. Working in Australia, 
with abundant material at his disposal and with the willing aid of 
some of the foremost of Australian botanists, he has endeavoured to 
co-ordinate the evolution of the Australian flora with the develop- 
ment of the physical conditions, and it is with his papers on this 
subject that I will now deal. 

Mr. Andrews had for years devoted himself as a geologist to 
unravelling the history of Australia as a land-mass, and he found in 
the development of the present land-forms and in the conditions in 
which they were produced a key to the various stages in the building 
up of the island continent. Whilst thus engaged, his attention was 
drawn to a remarkable relation existing in New South Wales between 
the arrangement of the purely Australian and extra-Australian 
plants and the physical, geological and climatic features of the region. 
This led him to reflect on the manner in which the Australian flora 
as a whole had responded to the different stages in the development 
of the continent, and he was induced to look to the Myrtacece and 
Leguminosce as orders especially well fitted for the investigation of 
this subject. 

In December 1913 his paper on " The Development of the Natural 
Order Myrtacese" was issued in the Proceedings of the Linnean 
Society of New South Wales. For him in this paper the predominant 
influence in plant- evolution has been neither Time, nor Heredity, 
nor Variation, nor Selection, but geographical environment. The 
evolution of floras represents the response of plant-life to variations 
in climatic and soil conditions during ages of changing geographical 
surroundings. Taking the position that cosmopolitan and genial 
climates at different geological periods tended to produce cosmopoli- 
tan or widely ranging floras, whilst variation in climate in the past 
tended to produce differentiated and localised floras, he applies this 
view to the differentiation of the Myrtacece from deduced generalised 
primitive forms of the Cretaceous age. It is argued that at this 
period the family, responding to the relatively uniform conditions of 
a mild and moist climate that prevailed over much of the globe, had 
a much wider range than it now has, and that it then covered the 
tropics as well as a large part of the present temperate regions. 

The manner in which the primitive types differentiated in response 
to the differentiation of climatic and other conditions since the late 
Mesozoic is then indicated. The early types would become more 
and more restricted to the regions that preserved their original 



318 PLANTS, SEEDS, AND CURRENTS 



environment, that is to say, to the present tropical latitudes. With 
the marked diversity of conditions characterising the later periods, 
local differentiation of the floras took place in such regions as 
Australia and South America, which became more or less isolated 
from neighbouring tropical areas. The Myrtacece underwent 
" divergent transformations." The fleshy-fruited forms, which, as 
it is presumed, were nearest to the original types, became character- 
istic of the warm regions of the globe. Their characters were those 
common to the numerous genera to which they have given rise, the 
Eugenias, the Myrtles, the Psidiums, etc. The capsular-fruited 
forms mark a later adaptation of the fleshy-fruited types to less 
genial conditions, to poverty of soil and to aridity of climate. They 
are for the most part Australia's response to the influences working 
out the differentiation of the Myrtacece, and we see them now in the 
genera Bceckia, Melaleuca, Eucalyptus, etc. In the successive differ- 
entiation of tribe and genus Australia, he holds, has played a great 
part in the history of the Myrtacece. 

There has been no attempt here to summarise a paper which 
bristles with so many points that it is difficult to handle it. But not 
the least important part of it is that in which Mr. Andrews throws 
down the challenge with regard to the older determinations of 
Eucalyptus in the Cretaceous and Tertiary formations of the northern 
hemisphere. After pointing out that the history of Eucalyptus is 
conveyed in the two kinds of leaves which characterise the genus, 
the earlier opposite leaves telling a story of the warm genial climates 
that prevailed during the Cretaceous and Tertiary periods, and the 
later alternate leaves with twisted stalks one of subsequent adapta- 
tion to the harsher and more arid conditions of Australia, he observes 
that "it is exactly the later more or less xerophytic and unstable 
form which has always been reported as existing in the Cretaceous 
and Tertiary beds of the northern hemisphere, beds strongly sugges- 
tive of moist, genial climates." Mr. Deane's paper on the " Tertiary 
Flora of Australia " (Proc. Linn. Soc. N.S.W., 1900) is quoted in 
this connection, and we are referred to Mr. Cambage's presidential 
address before the Royal Society of New South Wales in 1913. 

We have to face this objection, which, until it is sufficiently 
answered, will weigh heavily against our belief in the fossilised 
Eucalyptus leaves of the north. Yet it would not be antecedently 
improbable that Eucalyptus should repeat the story of two hemi- 
spheres, whether in the east and the west or in the north and the 
south, which is told in varying forms by Liriodendron, Liquidambar, 
Per sea, Sassafras, Libocedrus, Sequoia, and other plants. When one 
reflects, as Wallace and many others insist, that ancient and once 
widespread groups may in our time maintain themselves only in a 
few widely separated localities, it is not easy for the west and the 
north to abandon their ancient claim to Eucalyptus. 

In the following year (1914) Mr. Andrews issued a paper written 
on the same lines concerning the Leguminosce, a paper read before 
Section E of the British Association in August of that year and 
before the Royal Society of New South Wales in the following Novem- 
ber, and here as in his paper on the Myrtacece he expresses his great 



DIFFERENTIATION 



319 



indebtedness to Mr. R. H. Cambage. Like the Myrtacece, the 
Leguminosce are regarded as descended from a few uniform primary 
types widely diffused through the world in Cretaceous times and 
differentiating in later geological ages in response to the differentia- 
tion of conditions. We have here in geological time the same asso- 
ciated processes of differentiation of conditions and of differentiation 
of types. The Upper Cretaceous period, when the primary type 
had a wide range over the globe, was characterised by low-lying 
lands and by a mild, moist and genial climate extending from 
the tropics to the polar regions. Progressive differentiation of 
climate in later geological times, when high mountains, large con- 
tinents, and great deserts came into existence, found a response in 
the differentiation of the types, many of them responding in the 
present temperate latitudes to the changes in their environment by 
the development of large and important groups of xerophytes, the 
evolution taking place along divergent lines in different regions. 

In discussing the principles of distribution he lays stress on the 
probable great age in Australia of the " pantropical " genera and 
on the relative youth of the endemic genera. It is shown that in 
Australia the plants which respond to the xerophytic conditions 
that prevail there, such as the Eucalypti and the phyllodineous 
Acacia?, have only in recent geological times assumed their present 
leaf-forms. They represent Australia's response in the differentia- 
tion of plant-types that were originally widely spread in the tropics ; 
and the more recent development of such generic forms in compari- 
son with their parent pantropical types illustrates a principle that 
has long been recognised as a corollary of the theory of differentia- 
tion. If the theory is true, this is its natural consequence ; and the 
principle involved, namely, that antiquity does not connote change, 
has been already discussed in an earlier page of this chapter. 

Mr. Andrews returns to the attack on those who would deny to 
Australia the right to the sole possession of Eucalyptus. " The 
evidence " (he says) " is overwhelming against the probability of any 
dicotyledonous genus which is endemic in Australasia having existed 
in any other continent in either Cretaceous or Tertiary time." He 
maintains, and this is a strong point, that if xerophytic types, like 
those of Eucalyptus, the phyllodineous Acacias, Banksia, etc., had 
gained access to the waste areas of the other southern land-masses, 
and particularly South Africa, they would have found a congenial 
home. His general position as regards Australia may be thus 
summed up. He would hold that whilst the endemic vegetation of 
Australia has been developed within its limits as the result of its 
special conditions, the source of its affinities with South Africa and 
South America must as a rule be looked for in the common home 
of the type in the tropics. Differentiation of types in response to 
differentiation of conditions is evidently, to use my own language, 
the bed-rock of the views advocated by Mr. Andrews. To employ 
his own words : " Traced backward far enough, geographical environ- 
ment appears to be the key to evolution." 

The Natural Order and Darwinian Evolution. — It follows 
from the foregoing remarks that no plant-groups, in the sense of the 



320 PLANTS, SEEDS, AND CURRENTS 



great orders, could have been produced on the evolutionary lines 
implied in the Darwinian theory. To lay down, as the evolutionist 
does, that the order of development begins with the variety, varieties 
diverging into species, species into genera, and genera into natural 
orders, is to reverse the method followed in nature, since it implies 
that the simpler, least mutable, and least adaptive characters that 
distinguish the great orders are the last developed. This could 
never have been. Nature has ever worked from the simple to the 
complex, from the general to the particular. Had she followed the 
lines laid down by the Darwinian school of evolutionists, there 
would be no systematic botany. All would be confusion. There 
would be no distribution in the sense in which the term is generally 
understood, and the plant- world would be a world of monstrosities. 

In the differentiation of a generalised type by which natural 
orders break up into tribes, the tribes into genera, and the genera 
into species, our systematists have symbolised the process of pro- 
gressive differentiation of conditions which has taken place in the 
physical world, and this is the result we should expect in a world 
where adaptivity reigns supreme. Though we signify our approval 
of these systems by our daily use of them, we employ language and 
adopt lines of reasoning that are utterly opposed to all that these 
systems of classification stand for. In these respects our practice 
and our theory are as far asunder as the poles — our practice good, 
our theories indifferent. 

There lies beside me a very useful little book, written by a botanist 
of authority and intended for the use of students. In keeping with 
the teaching of the day, it is there explained how in the evolutionary 
process the natural order is built up by the varieties diverging into 
species, the species into genera, and the genera into groups of genera 
or orders, the species being taken as the unit of origin. Yet if we 
put this theory into practice in our plant-systems it would spell 
chaos. No typical natural order could be produced by such a 
method of evolution. The usual process of change in the plant- 
world, as in the physical world, has been from the general to the 
particular, and we should be quite as illogical in reversing the process 
for the plant as we should for its conditions. 

Let the reader take a natural order and endeavour to build it up 
from one of its own species on the lines suggested by the evolutionist. 
With the goal before him of the generalised type of the systematist, 
his theory would desert him at the start. What he would attain, 
if he persisted in his plan, would be something very different from 
our natural orders, a highly specialised type of organism nearing its 
extinction. In these respects our practice belies our theory. Were 
it not so, our studies of the plant- world would be profitless indeed. 

Yet it is not to be supposed that such a process is not in active 
operation in nature. Unfortunately for the systematist it is, and 
all the oddities in the plant-world are to be placed to its credit. 
But the point emphasised is that this is not the process that has 
given its impress to the plant-forms of the globe. We live in a 
differentiating rather than in a specialising world; and although 
specialisation is common enough, it is very far from being the prin- 



DIFFERENTIATION 



321 



cipal determining cause of the diversification of plant-forms. Let 
us look a little further into this matter. Nature displays in the 
island and in the continent the two influences of specialisation and 
differentiation at work. We should look rather for specialised 
genera in islands and for differentiated genera in continents. In 
the first instance we have illustrated the Darwinian view, where a 
species becomes so modified that it is given a generic rank; but 
there is much evidence to show that this is a road which leads to 
extinction, the specialised genus having, as a rule, a limited range 
and a limited duration. In the case of the differentiated genus of 
a continent we have a broad range and a promise of eternity. It is 
of such that the plant- world was mainly formed in the past, is largely 
composed in the present, and will be made in the future. Specialised 
genera may figure conspicuously in localities; but their corpses 
strew the path that nature has chiefly followed in the development 
of the plant- world. 

The great trouble is that we give the same value to products of 
very different origin and of very different standing ; the one transient 
and limited in range, the other permanent and wide-ranging ; the one 
representing nature's failures and the other her successes in stocking 
the world with its plants. Whilst specialisation means extinction, 
differentiation means a permanence of floral types that will hold the 
world as long as there are conditions for plant-life. Take, for 
instance, the monstrosities of the Tree Lobelias of Hawaii, of which 
some half a dozen genera have been developed in that group. They 
were born there and they will die there, and they have been unable to 
extend their range. These specialised genera make no effort to 
conquer the globe; yet we place them in a list of campanulaceous 
genera side by side with such a world-ranging primitive genus as 
Campanula. 

It would seem that monographers of orders may create their own 
difficulties by not recognising this difference between specialised and 
differentiated genera in a family. All their difficulties begin when 
they try to bring them into line. The specialised genera should be 
set apart and treated independently. 

Summary 

1 . The general nature and limitations of the differentiation theory 
are briefly discussed, and the author's connection with it is described. 
Stress is laid on his failure to recognise in his previous writings that 
although it explains the diversity of plant-forms there is much in 
distribution that it will not account for, distribution being also an 
expression of the influence of the arrangement of the continents 
during secular fluctuations of climate. The two subjects are accord- 
ingly individualised and treated separately, under the heads of 
Differentiation and Distribution, in this and the following chapter. 

2. The differentiation of a world-ranging generalised family type 
is regarded as a response to the differentiation of originally uniform 
conditions. The existing families are viewed as primitive and widely 
distributed and derivative and relatively localised. It is considered 

Y 



322 PLANTS, SEEDS, AND CURRENTS 



that in the derivative families the process of differentiation has often 
proceeded so far that the original family type is lost, being only non- 
represented in the characters uniting in one great plant-group a 
number of families, which, although they hold the world between 
them, respectively characterise different portions of it. In the 
family, in the tribe, in the genus, in the species, in the variety, and 
in the local race, we see the same principle at work, the process 
being illustrated in its last stage in the role of the polymorphous or 
highly variable species (pp. 313-14). 

3. Whilst we should expect to find a primitive family represented 
in all the continents, the absence of some of the derivative families 
is often to be looked for. To illustrate the argument we may take 
the flora of Australia, where there are world-ranging families, bearing 
a special Australian impress, associated with families of later develop- 
ment and of Australian origin, which represent an extensive regional 
modification of a primitive world-ranging type that has been lost in 
the differentiating process (pp. 315-16). 

4. In this connection attention is drawn to recent papers by 
Mr. E. C. Andrews on the development of the Myrtacece and Legumi- 
nosce with special reference to Australia. Adopting the view that 
the evolution of floras represents the response of plant-life to its 
physical environment during ages of changing geographical sur- 
roundings, he applies it to the differentiation of these two families 
from wide-ranging primitive forms of the Cretaceous period when 
relatively uniform climatic conditions prevailed. He challenges the 
correctness of the older determinations of Eucalyptus remains in the 
Cretaceous and Tertiary deposits of the northern hemisphere, and 
claims the genus as Australian-born (pp. 317-19). 

5. With this digression the author goes on to show that if the 
differentiation hypothesis is correct no natural order could have 
been developed on the lines implied in the Darwinian theory, which, 
as interpreted in recent works, begins with the variety and termi- 
nates with the order, a process that reverses the usual method of 
nature (pp. 319-20). 

6. Yet such a process, as is there implied, is common enough in 
the plant- world; but it accounts not for natural orders, but for all 
the oddities of plant-forms. It is here termed a specialising process 
in contrast with that of differentiation ; but it is the differentiating 
process that has been the principal determining cause of diversifica- 
tion in plants (p. 320). 



CHAPTER XV 



DISTRIBUTION 

The differentiation theory could of itself explain distribution only 
where a continuous land-area not affected by unstable climatic 
conditions is concerned. As our globe presents itself, three factors 
control and direct the operations of the differentiating agencies : 
(1) the divergence of the land-masses from the north; (2) the secular 
fluctuations of climate; (3) the barriers lying athwart the line of 
march of migrating plants. 

(1) The Divergence of the Land-masses. — Although the differ- 
entiation theory explains the diversity of plant-forms, it does not of 
itself account for their present distribution. It might do so if this 
were a comparatively orderly world with stable climatic conditions, 
and if the plants had differentiated in situ over a continuous land- 
surface. But a uniformly constituted plant- world of this descrip- 
tion does not exist, since differentiation is intensified as one recedes 
from the northern polar area, until in the southern lands of South 
America, South Africa, and Australia it displays its most pronounced 
effects. That floras become more and more dissimilar with distance 
from the pole is the result of the continuity of the land-masses in the 
north and their disseverment by broad oceans in the south. In 
other words, the continuity of the floras of the north and their dis- 
continuity in the south represent the response of the plant-world 
to the arrangement of the great land-masses. 

(2) The Secular Fluctuations of Climate. — If the first factor 
alone prevailed, distribution would not be such a very complex 
matter, since we could express it as the effect of the differentiating 
process controlled by the divergence from a common centre in the 
north of the great land-masses of the Old and the New World. But 
in so doing we should be ignoring a very important disturbing factor, 
namely, the secular climatic changes. During much of geological 
time there have been fluctuating conditions of climate which have 
produced a series of advances and retreats to and from the north 
polar area of the plants of the warm regions of the globe, regions 
that have ever been the great home of plant-life. 

At a time when a genial climate prevailed over the northern or 
land hemisphere the plants now represented in type in the warm 
latitudes occupied the regions beyond the Arctic circle. When this 
period gave place to cooler conditions the retreat to the south began ; 
and the plants, as the diverging continents pulled them more and 
more asunder, became more and more distinct from each other as a 

323 



324 PLANTS, SEEDS, AND CURRENTS 



result of the varying differentiating influences of the hemispheres of 
the east and the west. When the warm conditions returned, the 
plants advancing northward met again in the common gathering- 
ground around the pole, but modified by their different experiences 
in southern regions lying oceans apart. There they mingled together, 
the eastern and the western floras ; and when with the next climatic 
change they began again to retreat to their ancient home in the 
warm latitudes of the south, the east had borrowed from the west 
and the west from the east. The secular climatic changes have, 
therefore, tended in this way to mix together the floras of the 
globe. 

(3) The Barriers athwart the Course of Migrating Plants. 
— But another factor has intervened to disturb the effect of the 
influence of the divergence of the land-masses and of the secular 
fluctuations of climate on the operation of the differentiating agencies. 
The contrast between the plants of the eastern and western hemi- 
spheres may be, and has been, intensified in an irregular fashion by 
the presence in one and the absence from the other of obstacles in 
the line of retreat. During their sojourn in the north a huge Hima- 
layan range, or a large Mediterranean sea, or a great Sahara desert, 
may have been developed and lie athwart their line of march; or a 
lofty Cordillera, running with the meridian almost from pole to pole, 
may aid the migration between the north and the south. But 
always there will have been the great preponderance of land in the 
north, and always those two great diverging land-masses of the east 
and the west, ocean-parted in the south and meeting in the north. 
Thus the distribution of plants may now be expressed as the effect 
of the operation of the differentiating agencies under the control and 
direction exercised by the divergence of the land- areas from the 
north and by secular fluctuations of climate, the resulting migration 
of plants to and from the north being checked or aided in different 
degrees by the surface- configuration of the continents. 

The Views of Sir W. T. Thiselton-Dyer. — How the author 
came to recognise that distribution is something more than the 
work of the differentiating and dispersing agencies is stated in a 
later page. But it should be at once observed that the controlling 
influences, as above described, are those which Thiselton-Dyer has 
for years emphasised in his writings on distribution. Hooker's and 
Bentham's well-known views on the spread of the Scandinavian 
flora over much of the globe acquired increased significance in the 
author's mind when employed by Thiselton-Dyer in his essay in 
Darwin and Modern Science, as illustrating a general principle applic- 
able to plant- distribution in geological time. 

Distribution, a Problem of the Northern Hemisphere. — In 
the following pages the present author has endeavoured to give in 
his own words the views stated by Thiselton-Dyer in this essay. In 
the tropics, which have ever been the great home or " the area of 
preservation " of plant-life, the continents are separated by broad 
oceans. In the extreme north, where a permanent home has been 
rendered impossible through climatic conditions, the continents meet. 
With the land mostly in the north and the sea mainly in the south, 



DISTRIBUTION 



325 



with huge land-masses radiating southward and wide oceans stretch- 
ing northward, distribution becomes chiefly a problem of the north. 
We cannot get over this fact by raising problems in the south. They 
could only be subsidiary. The increasing differentiation of floras 
with distance from the Arctic pole leave us no choice in the matter. 
It cannot, therefore, be a subject for surprise that of the great land- 
masses of the south each tells its own story, and that the discontinuity 
between genera and species, so frequent in the south, diminishes as 
we approach the Arctic area. 

Any theory of distribution will have to explain the abandonment 
of share in the struggle on the part of whole groups of plants and 
animals that found a sanctuary long ago in the southern lands of 
South America, South Africa, and Australia. It will have to face 
the fact that these three extremities of the great land-masses diverging 
from their common centre in the north have become for plants and 
animals " cul-de-sacs," as Thiselton-Dyer terms them, from which 
there is no escape. It will have to explain why South America, 
South Africa, and Australia have become the abodes of lost causes, 
of causes that have been fought for and lost in the north. 

The Zoological Standpoint. — Zoologists have often appealed 
to the hypothesis of a north polar centre of dispersal in explanation 
of their difficulties. Dr. Scharff, in his recent work on The Distribu- 
tion and Origin of Life in America (pp. 23, 427), refers in this connec- 
tion to the views of Allen, Dahl, Haacke, Tristram, and Wilser, only 
to reject them as untenable. 44 There have been " (he contends) 
44 scores of great centres of dispersal in the world, and from them 
streamed forth new forms in every available direction. Northern 
animals advanced southward and southern forms northward, aided, 
no doubt, by the ever-changing conditions of climate and the gradual 
evolution of oceans and continents." 

Yet, if we allow for the occurrence of subsidiary centres, it can 
be scarcely said that these views are radically inconsistent with 
those advocated in these pages. Standing by themselves they can 
hardly do other than make the investigation of distribution a study 
of tangled results which may lead us anywhere. The method of 
reconstructing the land-surface from the facts of distribution is the 
least promising of all the modes of attacking the problem. The 
opposite plan is here followed. The very thoroughness of Dr. 
Scharff' s work appears to me to emphasise the hopelessness of ever 
solving problems of distribution by taking up the ends of the tangled 
skein. We must begin with a few general and simple premises that 
are beyond dispute, and work forward. Working backward seems 
to be the method least likely to evoke order out of the reigning chaos, 
and for one among many reasons that we do not yet know the real 
significance of many of the lesser facts of distribution, being often 
utterly at variance with one another in our interpretation of them. 

The Geological Standpoint. — Let us for the moment forget 
much about distribution, and start with the fact that there existed 
in Tertiary times in the Arctic regions a subtropical climate and a 
subtropical vegetation. Let us add to this the second fact that this 
vegetation is not to be found within the Arctic Circle now, but in 



326 PLANTS, SEEDS, AND CURRENTS 



southern regions separated by broad oceans from each other. Let 
us connect with these two facts a third, that this migration south 
has been associated with a secular change from warm to cold climatic 
conditions. The conclusion to which they inevitably lead is rejected 
by Dr. Scharff in the case of animals (p. 428) mainly on account of 
the absence of geological evidence. But we have the geological 
records on our side for the plants ; and if we hold the belief that the 
great change both in climate and in flora which has come over the 
north since Tertiary times has been repeated in the earlier ages of 
the world's history, we stand on much safer ground than if we were 
to assume that we are here face to face with a change unprecedented 
in the story of our planet. We are not concerned with the north 
polar regions as an evolutionary centre, but as the great mixing 
ground through the ages of the plants of the eastern and western 
hemispheres. 

Discontinuous Distribution. — Let us glance at the facts of 
discontinuous distribution. Whether we take a genus (A) which, 
although represented in the Tertiary deposits of the common meeting 
ground of the continents in the north, is now divided by the oceans 
in the south, or a genus (B) that is now hopelessly sundered and 
isolated in tropical regions and has, as far as is yet known, left no 
trace of its original existence in the north, or a genus (C) that is now 
restricted in the main to the continents of the temperate latitudes 
of the south, the lesson is the same. For discontinuity forms the 
essence of the problem, the error lying in treating extreme cases, like 
that of Ravenala, as things apart that require a special explanation. 
Such cases raise not side-issues, but the main question, the whole 
history of distribution being concerned with the effects of discon- 
tinuity increasing with distance from the north polar area. 

The simplest cases of discontinuous distribution are those illus- 
trated by such genera as Quercus, Fagus, Acer, Juglans, Tilia, etc., 
all represented in the Tertiary deposits of the extreme north, and 
now found on both sides of the great oceans to the south, reaching 
in some instances, as in that of Fagus, New Zealand and Fuegia. 
Less simple cases are those so frequently illustrated among tropical 
genera where the geological record, as at present known to us, is 
silent as to their original occurrence in the north. But it is legitimate 
to assume that the same principle has been at work here, and to 
infer with Thiselton-Dyer in his Philadelphia address that during 
the warm periods of the Miocene and earlier ages purely tropical 
types would have extended north to latitudes where the interchange 
between the Old and the New World would not be impracticable. 
The behaviour of Ravenala, which is represented by only two known 
species, one in Madagascar and the other in tropical South America, 
is repeated, though in a less striking degree, by numbers of tropical 
genera. We have, for example, Thespesia (Malvaceae), mainly 
American and Malayan, and Mammea (Guttiferw), equally shared by 
the New World and Madagascar. Then there are Chrysobalanus 
(Rosacea;) and Crudya (Leguminosos), which are chiefly American, 
two genera that are only known in the Old World from Africa and 
Malaya. Then there is Desmanthus, a leguminous genus, of which 



DISTRIBUTION 



327 



only one of the ten species occurs outside the New World, namely, 
in Madagascar. The number of genera mainly American which have 
one or two solitary representatives in the Old World is remarkable. 
Several remarkable cases of discontinuity could be cited from the 
tropics of the Old World. For instance, Canarina (Campanulacece) 
holds three species, found respectively in the Canary Islands, tropical 
Africa, and the Moluccas. 

Whether in the family, in the tribe, or in the genus, discontinuous 
distribution is a familiar feature in the plant-world of the southern 
hemisphere. A very ancient history is implied in the representation 
of the Proteacece by different genera in Australia, South Africa, and 
South America. Students of fossil botany are persistent in claiming 
a home for the family in Europe and North America in Cretaceous 
and Eocene times; but Thiselton-Dyer, with much to gain from 
such a valuable witness on behalf of his views, does not accept the 
evidence. As an example of a tribe we may quote his reference to 
the MutisiacecB, a tribe of the Compositce, characteristically southern 
in its distribution in South America, South Africa, and Australia. 
For the genera we may cite Librocedrus and Podocarpus of the 
Coniferce. Both of them are indicated amongst the fossil Tertiary 
remains of Northern Europe and North America, the first-named even 
in Spitzbergen; and both reach extreme southern lands — in the 
case of Podocarpus, Southern Chile, South Africa, and New Zealand, 
and in that of Librocedrus, New Zealand and Chile. 

In the foregoing remarks I have very inadequately illustrated the 
important subject of discontinuous distribution. Many of these 
genera are now restricted to tropical regions, and the geological record, 
as so far interpreted, tells no story of a sojourn in the north. But 
many of the genera of trees now confined to temperate latitudes of 
North America and Eurasia grew in Miocene times within the Arctic 
Circle, and the implication is that in the case of the dissevered 
tropical genera they also long ages ago were denizens of the north. 
The history of Sequoia, now restricted to California and its vicinity, 
but growing in Tertiary times in Arctic latitudes around the pole, is 
the story of a genus that has failed. So also there may have been a 
similar failure with some of the tropical genera that are now found in 
only one of the two hemispheres, either in the Old or in the New World. 

The Centrifugal Dispersion from the North during the 
last Ice Age. — The associated processes of centrifugal dispersion 
from the north and of differentiation with distance from the pole are 
well described by Prof. Harshberger in his Phyto geographic Survey of 
North America (p. 181) ; but he limits its operation to the last of the 
great migrations that was connected with the Glacial Period. As 
the herd of glacial plants moved south from the far north into each 
one of the continental masses, America, Europe and Asia, they were 
subjected (thus he writes) to a great variety of conditions, " the 
outcome being great differentiation of form and the development of new 
species." This dispersion from the north during the last great Ice 
Age has been the theme of Darwin, Asa Gray, Bentham, Hooker, 
and many other eminent men of science, a fact to which allusion will 
again be made at the close of the chapter. 



328 PLANTS, SEEDS, AND CURRENTS 



Application of the same Principle to Geological Time. — It 
is, however, the feature of the theory advocated by Thiselton-Dyer 
that this process of differentiation during the centrifugal dispersion 
of plants from the north has affected not merely one migration from 
the polar area, but those of all geological periods during which the 
land-masses have preserved the main characters of their present 
arrangement. Thus he would extend it to the Mesozoic Conifers, 
and even suggests it in the case of the Glossopteris flora of Permo- 
Carboniferous times. There is this to be said, however, in this last 
connection, that we here open up questions relating to the Antarctic 
continent, which Seward, in his recent monograph on the fossil 
plants collected during the recent expeditions, believes to have been 
the centre of the differentiation of the Glossopteris flora (see Brit. 
Mus. publications, 1914). But the occurrence of this flora in the 
Upper Palaeozoic beds of Russia and Siberia has been established, 
and there is something to be said in support of Thiselton-Dyer' s 
contention in his Philadelphia address that " an economy of hypo- 
thesis is best served by assuming a northern origin and a dispersal 
southward than by calling into existence a vast territory from the 
Indian Ocean." 

The Views of some Australian Naturalists. — A view, which 
is the very opposite of that advocated by Thiselton-Dyer is held by 
some Australian naturalists, who consider that " the community of 
austral life is explicable only by former radiation along land-routes 
from the south polar regions." Hedley, whose important paper on 
the palaeographical relations of Antarctica is here quoted (Linn. Soc. 
Lond., June 1912), calls as witnesses two genera, Fagus and Arau- 
caria, the distribution of which in the past and in the present is 
usually regarded as indicating their home in the north. Fagus and 
Araucaria, however, cannot be treated together in this connection, 
the first named belonging to the age of the Angiosperms, the second 
to the Mesozoic Conifers. Though Antarctica apparently does not 
share in the history of the plant- world since the appearance of the 
Dicotyledons in force in the Upper Cretaceous age, it took a part in 
the earlier periods, and whilst prevented from figuring in the history 
of the Angiosperms, it may have preserved a record of world-ranging 
Conifers, 

Let us take the case of Araucaria. In his Philadelphia address 
Thiselton-Dyer observes that if we go back to the Jurassic age, and 
turn to Coniferse, the structures of which lend themselves to recog- 
nition in the fossil state, " we find in Araucaria, a genus now repre- 
sented by a few species in both divisions of the southern hemisphere, 
abundant evidence that it was once widely dispersed in the northern." 
In this connection one may remark that four species of Araucaria 
are included in Knowlton's list (quoted by Harshberger, p. 176) of 
Cretaceous and Tertiary plants of North America known up to 1898. 
In the case of Fagus it will be sufficient to note that eleven species 
are referred to it in the list of fossil North American plants just 
mentioned. But the linking together of this genus with Araucaria 
in support of the Antarctic hypothesis raises another point. One 
might admit the presence of a Mesozoic flora of Conifers in the 



DISTRIBUTION 



329 



Antarctic continent without committing oneself to the view that 
Antarctica was a Tertiary abode of the flowering plants. Before 
quitting this subject it may be added that Mr. Hedley's treatment 
of the matter is mainly zoological, and that his arguments can only 
be fairly met in their complete form by one who is similarly skilled 
as a zoological investigator. 

Re-statement of the Views of Sir W. T. Thiselton-Dyer. — 
The position adopted by him in his contribution to Darwin and 
Modern Science may be again stated before we bring this chapter to 
a conclusion. He contends that by postulating the permanency of 
the general configuration of the earth's surface, and by assuming 
that fluctuating conditions of climate have supplied an effective 
means of propulsion from the north, a continuous and progressive 
dispersal of species from the land-centre in the north polar regions 
is inevitable. One may extend these remarks and say that if it can 
be shown, as undoubtedly the general trend of the facts of distribu- 
tion does show, that the divergence of plant-types responds to the 
divergence of the great land-masses from the north and that dis- 
similarity is intensified with distance from that pole, any evidence 
for a Tertiary Antarctic centre for the flowering plants would be 
discounted in advance. On this view the plant-types most differ- 
entiated would be those that had met most rarely in the common 
gathering ground of the north; that is, those of the tropics and of 
the southern hemisphere. 

It was the recognition by Bentham and Hooker of the continuous 
southward migration of the Scandinavian flora over a great part of 
the globe that supplied the key for this interpretation of distribu- 
tion; and it was, as Thiselton-Dyer remarks, from the geological 
researches of Heer that it received early powerful support as a general 
explanation of the geographical distribution of plants. Long ago, 
as is again shown, Asa Gray held that the preservation of fragments 
of the Cretaceous flora in Asia and America had its explanation in 
their having had a common source in the north. As shaped and 
promulgated in Darwin and Modern Science this theory removes 
more difficulties from the path of the student of distribution than 
any previous hypothesis. But it does even more, since in clearing 
the road it opens a field of investigation which will take many years 
to explore. How distribution may appear when regarded from this 
standpoint is exemplified in the comparative study of Carex and 
Sphagnum in the next chapter. 

Summary 

1. The differentiation theory could of itself explain distribution 
only where a continuous land-area not affected by unstable climatic 
conditions is concerned. As our globe presents itself, three factors 
control and direct the operation of the differentiating agencies : the 
divergence of the land-masses from the north, the secular fluctua- 
tions of climate, and the barriers lying athwart the line of march of 
migrating plants. The effect of the first is seen in the increasing 
differentiation of floras with distance from the pole, that of the 



330 PLANTS, SEEDS, AND CURRENTS 



second in the migration of plants to and from the common meeting 
ground of the eastern and western floras in the north, and that of 
the third in its isolating influence varying in degree on the South 
American, South African, South Asian, and Australian floras 
(pp. 323-4). 

2. The views of Thiselton-Dyer are here adopted. They embody 
those of Bentham, Hooker, and Asa Gray in a general principle 
applicable to plant- distribution in geological time. From this 
standpoint distribution becomes a problem of the northern hemi- 
sphere, and we cannot get over this fact by raising problems in the 
south (pp. 324-5). 

3. After remarking that zoologists have often appealed to the 
hypothesis of a north polar centre of dispersal, it is observed that 
the method of reconstructing the land-surface from the facts of 
distribution is the least promising of all modes of attacking the 
problem. The geological record is on the side of the views adopted 
in this chapter ; and if we hold that the great change in climate and 
in flora which has come over the north since Tertiary times has been 
repeated in the earlier ages of the earth's history, we stand on much 
safer ground than if we assume that we are here face to face with a 
change unprecedented in the story of our planet (pp. 325-6). 

4. It is observed that discontinuous distribution, which is then 
briefly dealt with, is the essence of the problem ; and it is remarked 
that the error lies in regarding extreme cases, like that of Ravenala, 
as requiring special explanation (pp. 326-7). 

5. The important feature of centrifugal dispersion from the north 
is again alluded to, in order to emphasise the point that the south- 
ward migration generally recognised as resulting from the last glacial 
period illustrates a principle that has been in operation through the 
ages. The opposing view, which is supported by some Australian 
naturalists and has been very ably advocated mainly on zoological 
grounds by Hedley, is then discussed. It holds that the community 
of austral forms of life is the result of radiation along former land- 
routes from the south polar region (pp. 328-9). 

6. A restatement of the position adopted by Thiselton-Dyer is 
then given, and it is urged that his views remove more difficulties in 
the study of distribution than any previous hypothesis (p. 329). 

LIST OF SOME OF THE WORKS QUOTED IN THIS AND IN THE 
PRECEDING CHAPTER 

Andrews, E. C, The Development of the Natural Order Myrtaceae, Proc. Linn. Soc. 
N.S. Wales, December 1913. 
The Development and Distribution of the Natural Order Leguminosse, Journ. Proc. 
Boy. Soc. N.S. Wales, November 1914. 

Cambage, R. H., Presidential Address, Roy. Soc. N.S. Wales, 1913. 
Acacia Seedlings, Proc. Boy. Soc. N.S. Wales, July 1915. 

Dyer, W. T. Thiselton-, Geographical Distribution of Plants, Seward's Darwin and 
Modern Science, 1909. 
On the supposed Tertiary Antarctic Continent, Journ. Acad. Nat. Sci. Philadelphia, 
XV., ser. 2, 1912. 



DISTRIBUTION 



331 



GtjppYj H. B., see list at the commencement of this volume. 

Harshberger, J. W., Phytogeographic Survev of North America : Leipzig and New 
York, 1911. 

Hedley, C, The Palseographical Relations of Antarctica, Proc. Linn. Soc. 
Lond., 1911-12. 

Schabff, R. F., Distribution and Origin of Life in America, 1911. 
Seward, A. C, Antarctic Fossil Plants, Brit. Antarc. Exped., 1910 : Nat. Hist. Rep., 
British Museum (Nat Hist), 1914. 



CHAPTER XVI 



THE INFLUENCE OF THE DIVERGENCE OF THE CONTINENTS ON THE 
DISTRIBUTION OF SPHAGNUM AND CAREX 

The predominance of Sphagnum on the middle slopes of Pico and 
on the higher parts of San Miguel and Terceira in the Azores first 
directed my attention to the distribution of Peat-mosses. Whilst 
subsequently studying the matter in Warnstorf's recent monograph 
on the Sphagnacece (Das Pflanzenreich, 1911), I became much im- 
pressed with the fact that the Sphagnum floras of the eastern and 
western hemispheres became more and more unlike as one receded 
from the Arctic regions. This led me to realise that I had completely 
ignored in my previous inquiries one of the most important factors 
in shaping distribution, namely, that concerned with the divergence 
of the two great land-masses of the globe from the north polar 
area. 

From the Peat-mosses I turned to the Carices, another world- 
ranging group of plants, and from them received the same reply. 
It came as a surprise to me that two groups, so far removed from 
each other in the scale of plant-life and differing so greatly in their 
capacities for dispersal, should respond in the same way to the 
arrangement of the two great land-masses of the Old and the New 
Worlds. It was a relief to learn that some months had not been spent 
in vain in the comparison of dissimilar things. From the stand- 
point of distribution their behaviour proved to be the same, the 
differences being only in degree. But perhaps the most welcome 
revelation of all was that many of the difficulties associated with the 
distribution of the higher plants, such as concern insular floras and 
the floras of South America, Africa, and Australia, reappeared, 
though in a less intense form, in the distribution of the humble Peat- 
mosses. Such uniformity of behaviour, independent as it is of degree 
of organisation and of dispersing capacity, deeply impressed me, 
and led to my reading over again Dyer's essay in Darwin and Modem 
Science on the geographical distribution of plants, the result of which 
is shown in the preceding chapter. 

Both Sphagnum and Carex respond to the same Law but in 
different Degrees. — From the tabulated results for Sphagnum 
and Carex given below, a few general inferences may be drawn. In 
the first place, both groups of plants respond to the law involved 
in the increase of dissimilarity between the east and the west as 
one recedes from the Arctic regions, their differentiation intensifying 
with the divergence of the land-masses from the north. Another 

332 



DISTRIBUTION OF SPHAGNUM AND CAREX 333 



Table Illustrating the Effect of the Divergence of the Land -masses 
from the North Polar Area on the Distribution of Sphagnum and 
Cabex. 

(The limits of the regions employed are as follows : — As Arctic and Subarctic are 
included Scandinavia, North Russia, Siberia, Canada, Labrador, and lands north; as 
Temperate, the rest of Europe and Mediterranean Africa, extra-tropical mainland of 
Asia excluding Japan, North America between Canada and the subtropical region 
next described; as subtropical North American, Georgia, Florida, the Gulf States, and 
Mexico; as South American, the mainland only, Central America and the West 
Indies being excluded ; as African, all except the Mediterranean province; and as 
Australian, also New Zealand and Tasmania.) 





Regions 


Percentage of Species 
occurring in both 
the East and West 
Hemispheres 


Data and Remarks 
(The denominator of the fraction 
equals the total number of species in 
that region. The numerator equals 
the number occurring in both hemi- 
spheres) 






Sphagnum 


Carez 




Arctic 


100 


80 


S. 22 : C. 42 
22 53 




A 

East and West 
Hemispheres 


Subarctic 


89 


29 


52 211 




Temperate lati- 
tudes 


59 


11 


S. 51 : C. 54 
87 502 






South America, 
Africa, Australia 


2 


4 


S. 3 : C. 6 
180 175 


Africa and Australia 
= East Hemisphere 




Arctic and Sub- 
arctic 


90 


52 


S. 46: C.102 
51 195 






Temperate lati- 
tudes 


70 


24 


S. 52: C. 54 
74 221 




B 

West 
Hemisphere 


Subtropical North 
America with 
Mexico 


34 


Jl 


S. 12: C. 7 

35 62 




South American 
mainland 


3(5) 


8(16) 


S. 3 : C. 6 
110 79 


South America is here 
compared as before 
with Africa ; but if the 
Eurasian species are 
included, the percen- 
tages would be in- 
creased as indicated 
by the figures in 
parentheses. 




Arctic 




93 


42 
45 




C 


Subarctic 




40 


60 
150 




West 
Hemisphere 


Temperate lati- 
tudes 




24 


54 
221 


Carex only 




Subtropical North 
America with 
Mexico 




11 


7 

62 






South American 
mainland 




8(16) 


6 
79 





Note. — The cases are very few where the species do not occur in corresponding latitudes in the 
two hemispheres. Since some of the species occur in more than one zone, the same species may 
figure more than once in the results for the northern hemisphere. In the southern hemisphere 
Africa and Australia together represent the eastern hemisphere. The South American results 
refer only to the southern hemisphere. If those held in common with Eurasia were added, the 
percentage would be increased as shown above. 



334 PLANTS, SEEDS, AND CURRENTS 



important principle is probably concerned in the fact that the 
more lowly organised Sphagna do not respond to the law to the same 
extent as the Carices. It may be that this arises from the greater 
capacity for dispersal of the spores of Sphagnum than the fruits of 
Carex ; but all such advantages would, I think, be discounted in the 
run of the ages. If we look at the table we notice that the northern 
hemisphere is almost large enough for the complete differentiation 
of Carex, but it is too small for Sphagnum ; and it would seem that 
the lower plants need a larger area for evoking the full effects of 
the differentiating process than the higher plants. It might even 
happen that the world is not large enough for a particular group of 
plants, and that a chaotic confusion of affinities in a geographical 
sense would arise which would disappear in a world twice the size. 
This involves the principle that lowly organised plants would be 
less plastic than higher plants in the same area, or, in other words, 
they would respond less to changes of conditions. The point that 
our world may not be large enough for the lower plants should not 
be forgotten, and some interesting deductions could be drawn 
from it. 

It will be seen from these pages that free use has been made of 
the materials supplied by Warnstorf and Kiikenthal in their mono- 
graphs in the Pflanzenreich on the Sphagnacece and the Caricoidece. 
Buried deeply in the mass of data contained in this splendid series 
of publications there lies the romance of plant- distribution, which 
the diligent student can unearth, should he possess the inclination 
and the patience. If any success attends my efforts to present as 
illustrating real living problems the facts so laboriously collated by 
the German investigators, I shall have paid back a little of my debt 
to the authors of these monographs. 

Explanatio v of the Table. — Though the table is mainly self- 
explanatory, it should be remarked that the materials as arranged 
in the monographs do not always lend themselves for precisely the 
same treatment, which explains the varying treatment in the columns. 
In the first place (A) all the species of North America and Eurasia 
are dealt with, excluding those of the subtropical and tropical 
zones. In the second and third places (B and C) only those of the 
west hemisphere are utilised. 

The insular factor comes so much into operation in the northern 
tropics, and there are so many disturbing influences affecting a 
comparison between the tropical mainlands of the east and the west 
in the northern hemisphere, that, except in the mainland of North 
America, the warm latitudes have been disregarded. Islands, large 
and small, introduce the effects of isolation in a way not presented 
by a continent; and the disturbing influences of the insular factor 
are again referred to in a later page of this chapter. The necessity 
of excluding the island from this table is well exemplified in the case 
of Sphagnum. If we were to include Japan in the Eurasian region 
and the Malagasy province in Africa, we should find that half of the 
endemic Eurasian species (thirty-three in all) did not extend outside 
Japan, and that one-third of the African endemic species (forty- 
seven in all) are restricted to Madagascar and the Mascarene Islands. 



DISTRIBUTION OF SPHAGNUM AND CAREX 335 



The general principle that the farther the continents recede from 
the north the fewer are the species common to the east and the west 
is strengthened by including in the table South America as repre- 
sentative of the west hemisphere and Africa and Australia with New 
Zealand as representatives of the east. But numerous other con- 
siderations arise; and in fact the subsequent discussion is mainly 
occupied with the distribution of Sphagnum and Carex in the southern 
hemisphere. Here, since the source of these floras is one of the 
principal points dealt with, the islands are often permitted to tell 
their story. 

Comparison of the East and West Hemispheres in the North. 
— It is legitimate, in a sense, to compare the endemism of the large 
land-masses of the southern hemisphere, South America, Africa, 
and Australia, since they are widely separated and independently 
situated; but it would be worse than useless to contrast the great 
land-masses of the north in their entirety, diverging as they do from 
a common centre in the polar area. I will take the case of Sphagnum. 
In the combined area of the North American and Eurasian land- 
masses there are, excluding the islands, 110 species, of which fifty- 
three are found in both hemispheres. A little consideration will 
show that the mere statement that 48 per cent, of the North 
American and Eurasian species are held in common, however true 
it may be, becomes pointless after an analysis of the details of distri- 
bution. Thus, of the fifty-three species held in common, forty-six are 
Arctic and Subarctic species, and twenty-two are practically circum- 
polar. Since, therefore, the species held in common between 
Eurasia and North America mostly congregate in the north, we 
would expect that the species held separately by these two great 
land-masses would gather in the south. This is indeed the case. 
Of thirty-nine species confined to North America, only two are found 
in Subarctic latitudes. The rest belong to the south, being especially 
numerous in the Southern United States. Warnstorf, who had no 
theory to support, is emphatic on this point. Whilst, as he says 
(p. 38), there is great agreement between the species of the Arctic, 
Subarctic, Atlantic, and Pacific regions of North America and 
Europe, in the Southern States of the Union and in tropical America 
endemism prevails. The rule in North America that the species 
it holds in common with Eurasia belong to the north, whilst those 
peculiarly its own belong to the south, is also illustrated in Eurasia. 
Of the seventeen species restricted to that continent only one is 
found in the cold latitudes of the north. 

It would be equally futile in the case of the Carices to employ any 
common value when contrasting the endemism of Eurasia and North 
America. This is sufficiently illustrated in the fact that the number 
of species which North America shares with Eurasia gradually 
decreases from 93 per cent, in the Arctic latitudes to as little as 
11 per cent, in the Southern United States and in Mexico. 

The Connections of the South American Sphagnum and Carex 
Floras. — The parallelism between Sphagnum and Carex is strikingly 
illustrated in the case of the connections of South America with the 
rest of the globe. In both genera the predominance of North 



336 PLANTS, SEEDS, AND CURRENTS 



American species tells a story of the stream from the north; and, 
since nearly all of them are also Eurasian, we find a noticeable pro- 
portion of Old World forms amongst the species migrating south. 
In both there is a connection with Africa of the slightest kind. In 
both also there is apparently an Australian and a New Zealand 
connection. 

The links of South America with the outside world, as exemplified 
by the Peat-mosses and the Carices, are here tabulated in a general 
way. There are about 110 species of Sphagnum and rather over eighty 
species of Carex known from this continent, of which in the first case 
eleven species and in the second case twenty-nine species occur 
outside it. Since the same species is usually recorded from more 
than one region, the totals here given exceed the number of species 
concerned. 



The Distribution of the non-Endemic South American Species of 
Sphagnum (11) and Carex (29) 





Sphagnum 


Carex 


North America 


7 


18 | 


Eurasia 


6 


11 


Sphagnum — 6 in Europe, 4 in Asia. 
Carex — 10 in Europe, 11 in Asia. 


Central America 


5 


11 




Australia and New 
Zealand 


2 


6 




Africa 


1 


1 


The Sphagnum species occurs in 
Central Africa. The Carex species 
occurs in South Africa. 



The facilities offered to migration from the north to the south by the 
great mountainous backbone of the western world and the results aris- 
ing have often supplied themes to the botanist. An almost unbroken 
chain of mountains and highlands, connecting Arctic and Antarctic 
lands, is to be found in the American continent, and there alone on 
our globe. The only break of importance in this great continuous 
mountain chain lies, writes Harshberger (p. 191), in the Isthmus of 
Panama, where there is a distance of about 300 miles occupied by 
rugged forest-clad hills, between the lofty peaks of Veragua and the 
northern extremity of the Andes in New Granada. We should 
accordingly expect, as this writer proceeds to say, that this great chain 
would form the most effective agent in aiding the southward migra- 
tion of the Arctic and north temperate vegetation. In other words, 
the plants of the north would have often followed this route south- 
ward along the lofty mountains and elevated uplands; and "we 
do find," as the same author continues, " not only that a large number 
of northern genera and many species are scattered along this route, 
but at the end of the long journey, in Southern Chili and Fuegia, 
they are found in numbers sufficient to form an element in the 



DISTRIBUTION OF SPHAGNUM AND CAREX 337 



flora of those countries." Doubtless birds have played the principal 
part in the dissemination of species along this route; but the high- 
lands of the Greater Antilles evidently serve as halting-places in the 
track of migratory birds across the Caribbean Sea. In his descrip- 
tion of the dispersal of Uncinia by birds, which is quoted in Note 37 
of the Appendix, Morris states that migratory birds on their way 
north and south between North and South America rest on the high- 
lands of Jamaica at elevations of 5000 to 6000 feet above the sea; 
and so exhausted are they that they can be caught with the hands 
(Nature, December 16, 1886). 

The Stream of Plants from the Far North down the Andes 
to Cape Horn. — The stream of species from high northern latitudes 
in North America down the Andes to Cape Horn is well illustrated 
both by Sphagnum and Carex. They are all species that are distributed 
round the pole in the Arctic and Subarctic regions, both of America 
and Eurasia. Half of the species of Sphagnum and a third of the 
species of Carex that have been found south of the Straits of Magellan, 
that is, in Fuegia, are thence derived. Whilst the main stream from 
the north follows the line of the Andes, the outside regions have caught 
the eddies ; and, as in the case of Sphagnum in South Brazil, where 
only 3 per cent, of the species occur outside South America, the 
endemism is intense. Some of the principal conclusions here drawn 
with reference to the southward trend of Sphagnum and Carex in 
South America are exemplified in the following table ; but naturally 
there is much that can be substantiated only by reference to the 
original memoirs of Warnstorf and Kukenthal. 



Table illustrating the Concentration in the Southern Part op South 
America op Arctic and Subarctic Species of Sphagnum and Carex 

THAT ARE BOTH EURASIAN AND NORTH AMERICAN 





Total number of 
known Species 


The North American and Eurasian Species 


Number and Per- 
centage 


Distribution in the North 




Sphagnum 


Carex 


Sphagnum 


Carex 


Sphagnum 


Carex 


South America 


110 


81 


6=6% 


11 = 14% 


Five species 
are Arctic 
and Sub- 
arctic and 

one is 
Temperate 


Eight 
species are 
Arctic and 
Subarctic 
and three 
are Tem- 
perate 


Andes only 


25 


51 


4 = 16% 


11=22% 


Patagonian 
Andes and 
Fuegia 


8 


30 


4=50% 


11=37% 



(A) As illustrated by Sphagnum. — Let us begin with the South 
American species of Sphagnum. Out of about 110 species, at present 
known, only six have been found outside the New World. They are 
S. fimbriatum, plumulosum, mexicanum, pulchricoma, torreyanum, 
and medium ; and of these five are Arctic and Subarctic species, 
found in all cases both in Eurasia and North America. Four of them 
reach the Patagonian Andes, and three extend across the Magellan 
z 



338 PLANTS, SEEDS, AND CURRENTS 



Straits into Fuegia. They may, like S. medium, follow the great 
mountainous backbone of the New World from the Arctic Sea to 
Cape Horn. This species after extending through the length of North 
America, from Alaska southward, reappears in the larger West 
Indian islands, and then travels along the Columbian, Bolivian, and 
Peruvian Andes at elevations of 10,000 to 11,000 feet, finally reaching 
Patagonia and Fuegia. Others, like S. fimbriatum, plumulosum, 
and torreyanum, may skip the tropical regions, and after leaving 
North America reappear in the Chilian and Patagonian Andes, or 
not present themselves again until they arrive in Tierra del Fuego. 
Some, like S. mexicanum, though they may not reach farther than 
the tropics of South America, exhibit a behaviour very suggestive 
of their future discovery far south. At home near the sea-level in 
Subarctic latitudes, this species attains an elevation of from 3000 to 
3500 feet in the West Indies and Central America, and altitudes of 
from 7000 to 10,000 feet in the Equatorial Andes. 

(B) As illustrated by Carex. — All that has been said respecting the 
streaming of species of Sphagnum down the Andes from high northern 
latitudes can be paralleled in the case of Carex. Thirteen of the 
eighty-one species described as South American occur outside the 
New World. Of these eight are Arctic and Subarctic plants that 
are found in all cases in those latitudes, not only in North America, 
but also in Eurasia. All of the eight have reached Patagonia and 
Southern Chile, and six have crossed the Magellan Straits into 
Fuegia; and it will be seen from the table that, as in the case of 
Sphagnum, these species from the far north form a considerable 
proportion of the Carex flora of Antarctic South America. Some, 
like C. macloviana, may travel with relatively little interruption from 
the shores of the Arctic Sea down the line of the Rocky Mountains 
to the Mexican highlands, where this species has been found at an 
altitude of 14,000 feet, and then along the Bolivian and Chilian Andes 
to Fuegia. Others, like C. goodenoughii, may extend in North 
America as far south as Colorado, reappearing in the southern tropics 
in Bolivia, before proceeding down the Chilian and Patagonian Andes. 
Some, like C. capitata, range southward from the North- West Terri- 
tory down the Rocky Mountains, next appearing in Central America, 
and following the Argentinian and Patagonian Andes into Fuegia. 
Rut others, like C. microglochin, C. magellanica, and C. canescens, 
display great gaps in their passage south from high northern latitudes 
to the Fuegian islands, since they skip the tropics altogether and 
after following the Rocky Mountains to Colorado next appear in 
Patagonia and South Chile. The streaming southward is equally 
well illustrated by species confined only to the New World. Thus 
C. gayana, after following the whole trend of the Rocky Mountains 
from Canada to New Mexico, reappears in the Chilian Andes at 
elevations of 8000 to 10,000 feet before it crosses the Magellan Straits 
and enters Fuegia. Notwithstanding the gaps, which doubtless will 
in some cases be filled up by the future investigator, we have here 
suggestively illustrated the streaming of the Carices down the great 
backbone of the New World from the shores of the Arctic Sea to 
Cape Horn. 



DISTRIBUTION OF SPHAGNUM AND CAREX 339 



The Connections between South America and the Australian 
Region. — This discussion of the route followed by both Sphagnum 
and Carex in reaching Antarctic South America from high northern 
latitudes raises the question in both cases of the Australian and New 
Zealand connections with Fuegia and the Southern Andine region. 
In both some of the species have established themselves either in 
Australia or in New Zealand ; and the point at issue is the significance 
of this fact. 

We will first take the case of Sphagnum. Two species that have 
reached Fuegia from Arctic and Subarctic latitudes, namely, S. medium 
and S. fimbriatum, are also found in South-east Australia and in New 
Zealand. There are no other connections between these two regions 
as respects Sphagnum, and it might at first appear that one region 
had received its species from the other. But a glance at the distribu- 
tion of both species makes it clear that just as they have traversed 
the whole length of the New World from Alaska to the Straits of 
Magellan and beyond, so they have reached Australia from its own 
side of the globe, or, in other words, from high latitudes in Asia 
by way of the Himalayas, in which last-named area they both 
exist. 

It can be similarly shown in the case of the Carices that four out 
of the six species, which the Australian and New Zealand regions hold 
in common with the southern part of South America (South Chile, 
Patagonia, and Fuegia), must have been derived from the same side 
of the globe by the way of Central and South-eastern Asia. The 
occurrence of these four species (C. canescens, cederi, pseudo-cyperus, 
pumila) in Kashmir, Turkestan, South China, etc., renders needless 
any appeal to South America as their possible source. It can also 
be claimed for South America that the first three of the four species 
named were derived overland from the north. Although they have 
not been recorded from the tropics of the New World all three are 
characteristic of temperate latitudes in North America; and in 
postulating for them a southern route by the way of the Mexican 
highlands and the Equatorial Andes, we should be merely assuming 
that they have done that which has already been shown to have 
been accomplished by C. macloviana and other Arctic species. An 
objection might be raised in the case of C. oederi, which is represented 
by a variety peculiar to New Zealand, South Africa, and extra- 
tropical South America ; but this is met in the subsequent discussion. 

The Case of Carex pumila. — Yet, although the evidence is 
sufficiently convincing that South America did not receive these three 
species of Carex across the Southern Ocean from the Australian and 
New Zealand region, in the case of the fourth species, C. pumila, 
there is a distinct suggestion that it performed the ocean traverse 
from New Zealand to Southern Chile. This Carex has only been 
recorded in the New World from Chile; whilst it has an extensive 
range in Eastern Asia from Manchuria to Formosa and Hongkong, 
whence its extension to Queensland and over the eastern portion 
of the Australian continent to Tasmania, and thence to New Zealand, 
could be readily assumed. Since, therefore, it would be highly 
improbable from the facts of distribution just given that Carex 



340 PLANTS, SEEDS, AND CURRENTS 



pumila reached the Australian and New Zealand region from Chile, 
there is good foundation for the view that it is a gift from either 
Australia or New Zealand, preferably the latter, to South America. 
Accepting that inference, the fact that it has been recorded only 
from the western side of the continent, namely, from Chile, clearly 
indicates the route taken in its ocean passage, that is, from the 
west, which is under the circumstances the only route rendered 
practicable by the winds, the birds, and the currents. 

The indications supplied by Carex pumila derive fresh interest 
from those offered in the cases of the two other species, C. darwinii 
and C. trifida, which, with the four before named, make up the six 
species held in common between southern South America and the 
Australian and New Zealand region. These two Car ices have been 
found nowhere else on the globe than in the southern extreme of 
the American continent, in New Zealand, and in the islands near 
and to the south of it. Presumably there has here been some com- 
munication between these two widely separated regions; and the 
question that at once presents itself is whether South America 
supplied these two species to the New Zealand region, or whether 
it received them from that source. In either case it must be assumed 
that the sea-bird that transported the seed followed the westerly 
winds in its ocean traverse. This being granted, the case of C. darwinii 
raises a curious point. Since this species is well distributed over 
the Southern Andine region and in Fuegia, and since it occurs only 
in the Chatham Islands in the New Zealand and Australian region, 
the seed must have been carried eastward from Cape Horn. This 
route involves an ocean passage twice as great as that which would 
be implied in the passage westward against the westerly winds from 
Cape Horn to the Chatham Islands. But it would be assisted by 
the several islands in the Southern Ocean that serve as resting- 
places for the sea-birds that are ever flying round the globe in the 
latitudes of the Roaring Forties. The evidence of the other species, 
Carex trifida, is indeterminate, since it is well distributed in South 
Chile and the Falklands Islands in the one region, and in New Zealand 
and the neighbouring Antarctic Islands in the other. 

The direct Sphagnum and Carex Connections between Fuegia 
and the New Zealand and Australian Region. — From the above 
remarks it may be inferred that the parallel already traced between 
Sphagnum and Carex may be further extended to the species common 
to the southern extreme of South America and the Australian and 
New Zealand region. But the parallel is not complete. Whilst 
it has been shown that the two species of Sphagnum common to 
these widely separated regions must have been derived in each case 
from northern latitudes on the same side of the globe, South American 
from North America and Australian from Asia, this applies to only 
three of the six Carices common to the two regions. In the case of 
the others a communication across the Southern Ocean is implied, 
in one species from Australia or New Zealand to Chile, in another 
from Fuegia to the New Zealand area, whilst in the third there is 
nothing to indicate which region was the giver and which was the 
recipient. 



DISTRIBUTION OF SPHAGNUM AND CAREX 341 



The South American and African Connection. — Before leaving 
the subject of South America reference may be made to another 
point of similarity between Sphagnum and Carex, which concerns 
the scanty connection with Africa in the sense below defined. With 
both genera the two continents hold but a single species in common, 
namely, Sphagnum pulchricoma and Carex cederi. The first named, 
which is characteristic of the Southern United States and of tropical 
South America, has only been recorded from one locality outside the 
New World, namely, in the Lake District of Central Africa. The 
second is a typical North American and Eurasian species of Carex 
that has extended south as far as Tasmania and New Zealand and 
South Africa in one hemisphere, and as far as Patagonia in the other, 
being represented in all three regions by the same peculiar variety. 
For reasons to be now given it is held that this variety originated 
independently in South America and New Zealand, but was supplied 
from Patagonia to South Africa. Concerning the parent species 
there is no necessity to appeal to any transference across the Southern 
Ocean between extra-tropical South America and the Australian 
and New Zealand region, since the two regions could have derived 
it from northern latitudes on their own sides of the globe, the species 
being widely distributed in North America and in Northern and 
Central Asia. As regards its occurrence in South Africa, however, 
the indications are that this region received the variety across the 
ocean from Patagonia, as it is not recorded from any part of the 
African continent except from the high mountains of Basutoland, a 
matter dealt with in a later page. Reference will also be made 
below to the significance of the existence of the New World species 
of Sphagnum (S. pulchricoma) in Central Africa. 

The African Peat-mosses and Carices. — This brings us to the 
discussion of the representation of the Peat-mosses and Carices in 
the African continent ; and here again the behaviour of the two genera, 
offers a striking parallel, since they illustrate in a similar way that 
remarkable isolation which Africa so often exhibits in its flora as 
well as in its fauna. By Africa, we mean Africa with the Mediter- 
ranean Littoral excluded. This Mediterranean province of the 
European region receives from Europe species of Sphagnum and 
Carex that as a rule have failed to penetrate farther south. Thus 
species of Sphagnum, like S. rufescens and S. turgidulum, which are 
widely distributed over Europe, cross the Mediterranean only to 
reach Tunis and Algeria. However, although the great majority 
of the European Carices have been compelled to halt in North Africa 
after crossing the Mediterranean, a few have penetrated to the south 
of the continent. 

The Check to the Southward Advance of the Carices into 
Africa. — Just as in the New World the Carices from the north have 
been ever pressing south, so in the Old World the northern Carices 
have been ever endeavouring to reach the interior of Africa; but 
they have in nearly all cases been rolled back by the obstacles 
presented by the Atlas ranges and the sandy wastes of the Sahara 
and of Libya. Not more than 13 per cent, of the European species 
of Carex that have established themselves in the southern region 



342 PLANTS, SEEDS, AND CURRENTS 



bordering the Mediterranean have been able to penetrate the con- 
tinent and to reach South Africa, the oases of the Desert and the 
northern slopes of the Atlas representing as a rule their southernmost 
outposts. Thus of about thirty European Carices that have spread 
to North Africa only four (C. divisa, vulpina, externa, acutiformis) 
have reached South Africa by travelling along the length of the con- 
tinent. There is no prospect with any of the four species that South 
Africa received them across the Southern Ocean, either from South 
America or from Australia and New Zealand, since they have not 
been found there as indigenous plants. All the others, including 
species like C. pendula, sylvatica, pseudo-cyperus, vesicaria, halleriana, 
and diluta, have either been checked on the Mediterranean border, 
or have come to a standstill on the slopes of the Atlas, or have made 
their last halt in the Libyan oases. 

The Isolation of Africa. — The isolation of Africa, excluding the 
Mediterranean province which belongs botanically to Europe, is 
well displayed in the behaviour of the genera Sphagnum and Carex. 
Though, considering the great area concerned, the representation is 
poor, Africa holding about 9 per cent, of the known species of 
Sphagnum and only 4 per cent, of the Carices, yet the species are fairly 
well distributed. Thus in both cases about half are found in the 
tropical portion of the continent, and about a third in the southern 
part. The degree of endemism displayed is also very similar, since 
both groups of plants are represented by thirty-one species, and of 
these six extend outside the continent in the case of Sphagnum and 
seven with the Carices. 

In the following table Africa is compared with the other two great 
land-masses of the southern hemisphere, South America and Australia, 
as regards the proportion of its Sphagnum and Carex floras that is 
not confined to the continent. As far as South America is concerned, 



Comparison in the case of South America, Africa, and Australia, of the 
Proportions of non-Endemic Species, that is, of Species extending 
outside these regions 





Sphagnum 


Carex 






Total 


Extending out- 
side the region 


Total 


Extending out- 
side the region 


Islands excluded as 
below named 




Number 


Percentage 




Number 


Percentage 


South 
America 


110 


11 


10 


81 


29 


36 


Falkland Is., Juan 
Fernandez, Gala- 
pagos, etc. 


Africa 


31 


6 


19 


31 


7 


23 


Madagascar, Masca- 
rene and Atlantic 
Is., etc. 


Australia 


24 


11 


46 


28 


19 


68 


Tasmania, New Zea- 
land, etc. 



DISTRIBUTION OF SPHAGNUM AND CAREX 348 



these results can only be considered as approximate ; but it is prob- 
able that the effect of future discoveries will be to make the endemism 
yet more pronounced. The figures, as far as they go, indicate that 
the intensity of the endemism is greatest in Africa for the Carices 
and in South America for the Peat-mosses. But by taking other 
matters into consideration Africa gives promise of standing first also 
with Sphagnum. Thus, whilst the species connecting both South 
America and Australia with the outer world often range over much 
of the globe, most of the African Peat-mosses that extend beyond 
the limits of the region, as here defined, do not reach farther than 
Madagascar and the Mascarene Islands. Africa owns not one of the 
ten or a dozen world-ranging species of Sphagnum. These facts 
distinguish the continent in a conspicuous manner from both South 
America and Australia. 

The Necessity of excluding the Insular Element when 
comparing the sphagnum an© carex floras of continental 
Regions. — The insular element is removed from this table. The 
island by the intensity of its endemism is always a disturbing influ- 
ence in discussions regarding the floras of continental regions. The 
effect of linking New Zealand with Australia, Madagascar with Africa, 
and Japan with Eastern Asia, is to produce results quite out of pro- 
portion to the size of the disturbing area. It has already been pointed' 
out in the case of Sphagnum that if we included Japan in Asia andi 
the Malagasy province in Africa half of the known Eurasian species; 
would be recorded only from Japan, and one-third of the species 
peculiar to Africa would be found only in Madagascar and the 
Mascarene Islands. So also with the African Carices peculiar to 
that region, their number would be increased from twenty-five to 
forty if we added those restricted to the Malagasy province. As 
shown in the table for the Australian region given on a later page,, 
the effect of adding the New Zealand Carices to those of Australia 
would be to double the number of species. To have employed the 
combined results for Australia, Tasmania, and New Zealand, in? 
making the above comparison with South America and Africa,, 
would have caused a drop in the percentage of non-endemic species 
from forty-six to nineteen in the case of Sphagnum and from sixty- 
eight to thirty-four in the case of Car ex. 

Then it should be remembered that with oceanic archipelagos, 
like the Azores, it may make a great difference in the connections; 
of a whole continental flora if we link them to a continent with which 
they have little in common (see Note 22 of the Appendix). The 
insular factor, in truth, raises considerations other than those specially 
dealt with in this chapter. It may, however, be remarked that both 
Sphagna and Carices respond in a similar way to the isolating influ- 
ences at play in oceanic islands. We find peculiar species of both 
genera associated on islands in all the oceans, as in the Azores and 
St. Helena in the Atlantic, in Bourbon in the Indian Ocean, and in 
Hawaii in the North Pacific. 

We will now look a little closer into the behaviour of the genera 
Sphagnum and Carex in Africa, more especially as regards the con- 
nections established by the non-endemic species with regions outside 



344 PLANTS, SEEDS, AND CURRENTS 

the continent, North Africa being regarded as European in a floral 
Bense. These are indicated in the table below given. 



The Distribution of the non-Endemic African Species of Sphagnum (6) 

and Carex (7) 





Sphagnum 


Carex 




North Africa 


— 


4 


Included in the European floral region. 


Eurasia 


— 


6 


For Carex, Europe, 5 ; Asia 5. 


North America 


1 


1 




South America 


1 


1 




Australia and New 
Zealand 




2 


For Carex, Australia, 1 ; New Zea- 
land, 1. 


Madagascar and the 
Mascarene Islands 


5 


1 


For Sphagnum, Madagascar, 3 ; and 
Mascarene Is., 4. 


Amsterdam Island 


1 






Teneriffe 


1 







The outside Connections of the African Peat-mosses. — The 
Sphagnum connections beyond the continent first claim our attention. 
Of thirty-one species recorded from Africa, as geographically here 
defined, only six form connections with the outside world, four-fifths 
of the species being endemic. Of the six concerned, four merely link 
the continent with Madagascar and the Mascarene Islands (Bourbon, 
Mauritius, and Rodriguez); one of them, S. pappeanum, occurs 
on Bourbon and Rodriguez, on Teneriffe, and on Amsterdam, an 
island in the centre of the Indian Ocean; whilst the sixth, S. pul- 
chricoma, is a characteristic North and South American species that 
has only been recorded in Africa from the Tanganyika district. 
The limited nature of the external connections of the African 
Sphagnum flora is thus apparent ; and it serves to emphasise the view 
that Africa stands first among all the great continents as respects the 
isolation of its Peat-mosses as well as of its Carices. 

It is noteworthy that eighteen of the thirty-one African species 
of Sphagnum belong to the subsection Subsecunda, the largest and 
most differentiated of all the ten subsections of the genus and holding 
one-third of the species. Though it has active centres of differen- 
tiation in all the great continents and is more uniformly spread over 
the world than the other subsections, these centres are not connected 
by world-ranging species. Not one of the ten species of Sphagnum 
possessing the widest ranges belongs to the subsection Subsecunda, 
and not one of them is African. This isolation of Africa must be 
associated with the circumstance that the majority of its species 
belong to a subsection that is practically closed to the outside world. 
A further implication of this fact will be noticed below. It will be 



DISTRIBUTION OF SPHAGNUM AND CAREX 345 



sufficient here to restate our present position that in its limited con- 
nections Africa offers a great contrast with South America and 
Australia, which are in both cases linked by a number of species with 
the great land-masses of the north. Africa, it would seem, is a lonely 
continent as far as the Peat-mosses are concerned. 

The outside Connections of the African Carices. — Coming 
to the African Carices, we find that although the proportion of those 
that extend beyond the limits of the continent, as here defined, is 
about the same as in Sphagnum, the genus is brought by the con- 
nections of its outside species more in touch with the rest of the 
world. The seven species concerned, Carex divisa, vulpina, cernua, 
externa, cederi, acutiformis, boryana, are, with the exception of the last, 
wide-ranging Eurasian species that in one or two cases include 
Australia and sometimes even North and South America in their 
range. The only special connection is that of C. boryana, which 
extends merely to Madagascar and the Mascarene Islands. 

But in one respect the African Carices repeat in a remarkable way 
the behaviour of the Peat-mosses. In view of its isolation one would 
have expected Africa to be the home of the older types of these 
genera. But the contrary seems to be the case. Just as with 
Sphagnum nearly 60 per cent, of the African species belong, as 
already shown, to the largest and most vigorous subsection of the 
genus, so with Carex more than half of the species belong to the 
youngest, most vigorous, and most generally distributed of all the 
four subgenera, namely, Eucarex, a subgenus holding two-thirds of 
all the known species of Carex, 800 in all. It is remarkable that 
Primocarex, the oldest subgenus, almost fails in Africa. It would 
thus seem that the invasion of Africa by the Carices and the Peat- 
mosses took place during the later stages in the history of the two 
genera, and that the occupation of the continent has been followed 
by a period of isolation extending to our own times. This similarity 
in behaviour on the part of two groups of plants so divergent in 
character is a fact of importance. 

In the case of Carex the limitation of the species to the continent 
often seems to be unaccountably abrupt. Thus, there are four 
species (C. echinochloe, boryana, longipedunculata, and simensis, 
that are evidently distributed over the highlands of tropical Africa 
from the Cameroons to Abyssinia and have been found on Ruwenzori 
and Kilimanjaro at altitudes of 7000 to 10,000 feet. Though they 
extend practically to the eastern and western limits of the continent 
only one of them, C. boryana, passes beyond them ; but it does not 
travel farther than Madagascar and the Mascarene Islands. In two 
of the islands just named, Bourbon and Mauritius, this species meets 
C. brunnea, one of the most widely distributed of the Carices in warm 
latitudes. Ranging far and wide over Asia, it reaches Australia 
across the Malayan region, and finally establishes itself on the Hawaiian 
Islands in mid-Pacific. Yet there is no record of C. brunnea from the 
African mainland. There must be some important principle in- 
volved in the circumstance that Carices find it so difficult to enter 
the African continent, and so difficult, when there, to leave it. 

Sources of South African Carices and Peat-mosses. — An 



346 PLANTS, SEEDS, AND CURRENTS 



interesting question presents itself in connection with the sources of 
the Peat-mosses and Carices of South Africa, since there are two 
alternatives. Their ancestors may have come from the north, over- 
land across the continent, or they may have traversed the Southern 
Ocean in their passage from either the South American or the 
Australian region. Here an appeal must be made to the connections 
of species outside the continent. 

(A) The Carices. — In the case of Carex the question has been 
already raised and answered with respect to four species, C. divisa, 
vulpina, externa, and acutiformis, which are European species that 
having reached North Africa extended their range to the southern 
part of the continent, not one of them having been found either 
in South America or in the Australian region. Neither of the two 
other species concerned, C. cernua and C. cederi, gives a decisive reply. 
Thus the first named is a wide-ranging species, which, in the form 
of a fairly well- distributed special variety has obtained a slight 
hold in Australia in a single locality in New South Wales, a some- 
what better footing in New Caledonia, and a secure establishment 
in South Africa. Here the indications are indeterminate; but the 
scale turns against the trans- oceanic hypothesis, since it seems more 
feasible that Asia served as the common focus of dispersal. The 
testimony of the second species, C. cederi, is also uncertain. Found in 
North America, Europe, and Asia, this Carex is represented by a 
special variety, cataractaz, in different localities in South Chile and 
Patagonia, in a single locality in South Africa (Basutoland), and in 
various localities in Tasmania and in the Alps of New Zealand. Here 
it would seem most likely that whilst South Africa derived the variety 
across the ocean from Patagonia, the species reached Chile overland 
from North America, and Tasmania from Central Asia, and that it 
underwent the same varietal change in both those southern regions. 

The conclusions to be formed from the outside connections of the 
six South African species of Carex here concerned, are that four only 
could have been derived overland from Europe, that one of them 
probably hailed across the South Atlantic from Patagonia, and that 
the sixth was perhaps Asiatic in origin. On the whole, it would 
appear that South Africa has mainly derived its Carices overland 
from the northern hemisphere. 

(B) The Peat-mosses. — The South African Peat-mosses tell the 
same story. Of the five species found outside the continent none 
occur in either South America or in the Australian and New Zealand 
region. Evidently South Africa has been stocked with its species 
of Sphagnum from the north. Of these five species Madagascar 
and the Mascarene Islands hold all. One of them, S. pappeanum, 
which oceurs on the mountains of East Africa, as on Ruwenzori, 
has a most remarkable distribution. Outside the continent it has 
been recorded only from the islands of Teneriffe, Bourbon, Rodriguez, 
and Amsterdam. 

The Mystery of Sphagnum pulchricoma. — Before quitting 
this subject allusion should be made to the solitary Sphagnum con- 
nection between the continent of Africa and the New World. This 
is the more strange, since Africa, if we exclude the Mediterranean 



DISTRIBUTION OF SPHAGNUM AND CAREX 347 



Littoral, has no connection through the Peat-mosses with either 
Europe or Asia. The species concerned is S. pulchricoma, which is 
widely spread in America (United States, Equatorial Andes, Brazil, 
Paraguay, etc.), and occurs also on the west side of Lake Tanganyika 
in Central Africa. With the exception of its single African habitat 
it is, as far as is known, exclusively a New World species. 
Evidently before full weight can be attached to its sporadic 
occurrence in Africa, the matter would require further elucidation. 

Sphagnum and Caeex in Australia and New Zealand. — There 
is a good deal of parallelism between the behaviour of Sphagnum 



Distribution of the Australian, Tasmanian, and New Zealand 
Species of Carex and Sphagnum 







Endemic 
Species 


Distribution of the non 
Endemic Species 




Species common to 
Australia, Tasmania, 
and New Zealand 




Total number 
of Species 


Number 


Percentage 


Asia 


Europe 


North America 


South America 1 


Africa (south) 


Japan 


Australia, Tasmania, 
New Zealand 


Australia, Tasmania 


Australia, New 
Zealand 


Tasmania, New 
Zealand 


Carex : — 




























Australia . . 


28 


9 


32 


15 


5 


5 


3 


1 


13 


7 


1 


3 




Tasmania . 


9 






5 


3 


2 


3 


1 


5 


7 


1 




1 


New Zealand with 
the islands . 


42 


27 


64 


10 


6 


6 


5 


1 


9 


7 




3 


1 


New Zealand alone 


41 


24 


59 


10 


6 


6 


4 


1 


9 


7 




3 


1 


Combined region . 


61 


40 


66 


18 


8 


8 


6 


2 


15 










Sphagnum: — 




























Australia . 


24 


13 


54 


6 


5 


5 


1 




6 


3 


2 






Tasmania . 


12 


5 


42 


2 


2 


2 






2 


3 


2 






New Zealand with 
the islands . 


19 


11 


58 


5 


5 


5 


1 




5 


3 








New Zealand alone 


17 


9 


53 


5 


5 


5 


1 




5 


3 








Combined region . 


42 


34 


81 


8 


7 


7 


2 




8 











The above table illustrates three of the main features of the Carex and Sphagnum 
floras of the Australian and New Zealand region — 

( 1 ) The degree of endemism ; 

(2) The distribution of the non-endemic species outside the area concerned; 

(3) The connections between Australia, Tasmania and New Zealand, that is to 

say, the number of species they have in common. 



1 The southern part of South America. 



348 PLANTS, SEEDS, AND CURRENTS 



and Carex in the region of Australia and New Zealand, and there are 
also some instructive differences. The principal features are shown 
in the table given above. If we first take the combined region we 
notice that whilst only 7 per cent, (three out of forty-two) of the 
species of Sphagnum occur in both Australia and New Zealand, with 
Carex 18 per cent, (eleven out of sixty-one) are recorded from both 
regions. This would seem to indicate that Sphagnum has yielded 
more than Carex to the differentiating influences; but the opposite 
tendency is brought out in the table as respects New Zealand, where 
Carex would appear to have a slight advantage in this respect. There 
is little, therefore, to be gained by dwelling on this point. 

In the case of New Zealand it makes no material difference whether 
we include or omit the islands lying to the east and south (Chatham, 
Antipodes, Campbell, Auckland, etc.). It should, however, be noted 
that, as far as is shown in KukenthaPs monograph, these off-lying 
islands, as a rule, contain no species of Carex which does not exist 
in New Zealand, the only exception being the Chatham Islands, 
which alone in this region hold the Fuegian Carex darwinii. These 
out-lying islands, therefore, are not known to possess any peculiar 
species of Carex. It is different with Sphagnum, since Antipodes 
Island and the Chatham Islands hold in each case a peculiar species 
of the genus. In one or two cases the New Zealand Carices have 
spread to Norfolk and Lord Howe Islands, thus indicating a tendency 
to extend to Australia. 

The column that is devoted to Japan in the table is merely in- 
tended to emphasise the Asiatic connection. It is brought out in 
the text that both Japan and Australia derive most of the species 
held in common by them from the Himalayan region. 

The Geographical Connections of the Australian and New 
Zealand Peat-mosses and Carices. — But the difference between 
Sphagnum and Carex in the Australian and New Zealand region is 
only one of degree, since the geographical connections are closely 
similar. Whilst with Sphagnum all of the eight species found outside 
the region are Asiatic, seven being European, and seven North 
American, with Carex eighteen of the twenty-one non-endemic 
species are Asiatic, eight are European, and eight North American. 
There is seemingly in both cases a connection between the Peat- 
mosses and Carices of this region and those of the southern extremity 
of South America. There is only a very slight connection with South 
Africa in the case of Carex and none for Sphagnum. For genera so 
unlike there is, therefore, at first sight a close correspondence between 
their relations outside the Australian and New Zealand region, a 
correspondence which is not lessened by an examination of the details. 
Before discussing the predominant Asiatic connections, a feature 
common to both genera, I will deal with the South American and 
South African relations. 

In the first place there is the South American connection, apparent 
or real. As already shown in the case of Sphagnum, the two 
Australian and New Zealand species (S. medium, fimbriatum) which 
occur in Fuegia are widely spread Eurasian and North American 
species that could have reached their present homes in the south 



DISTRIBUTION OF SPHAGNUM AND CAREX 349 



from Asia and North America, the postulate of a traverse of the 
Southern Ocean being quite unnecessary. It has also been before 
pointed out that of the six species of Carex, which Australia and 
New Zealand possess in common with the southern part of South 
America, four could have been derived from Central and South- 
eastern Asia, and that the question of a South American origin 
could only be raised concerning two species, C. darwinii and C. trifida. 
Whilst it is highly probable, as previously shown, that the Chatham 
Islands, its only locality in that region, received the first species from 
Fuegia, the evidence respecting the second is indeterminate. 

The connection between the Australian and New Zealand region 
and South Africa is not illustrated by Sphagnum, and it affects only 
two species of Carex (C. cernua and C. cederi); but it has already 
been indicated that the evidence, though not decisive, tells more 
against than in favour of a trans-oceanic connection, since the 
original forms of both species could have reached the Australian and 
New Zealand region from Asia. 

The Asiatic Connections of the Australian and New Zealand 
Region. — By far the most important are the Asiatic connections 
of this region. As before remarked, all the species of Sphagnum 
and nearly all the Carices that occur outside its limits are found in 
Asia. There is no special connection with either Europe or North 
America which is not also Asiatic, all the species so concerned being 
widely distributed in the northern hemisphere. Asia, therefore, 
represents the immediate source of the Australian and New Zealand 
species of Sphagnum and Carex, since derivation from southern 
South America and from South Africa is altogether excluded for the 
Peat-mosses and for all but 3 or 4 per cent, (two or three out of 
sixty- one) of the Carices. 

When we examine the matter more closely, we find that all of the 
outside species of Sphagnum and that fifteen of the twenty-one out- 
side species of Carex occur in Japan, a fact that merely indicates a 
common centre of dispersion in Central Asia for the representatives 
of the genera reaching Japan and the Australian and New Zealand 
region. Of the Himalayan region as the centre of departure from 
which the same species has often travelled north-east to Japan and 
south-east to Malaya and Australia, more will be said. The route 
is determined in each case from the distribution of the species of 
Sphagnum and Carex that are concerned. In the case of Sphagnum 
there are four species — S. fimbriatum, papillosum, cymbifolium, 
medium — that have found their way to either Australia or New 
Zealand from South-eastern and Central Asia. All of them are 
spread far and wide over the northern hemisphere in North America 
and in Eurasia, and all have spread from the same Asiatic centre to 
Japan as well as to the Australian and New Zealand region. The 
two first named, however, present great gaps between their occur- 
rence in the Himalayas and Burma and in New Zealand. The third 
shows a similar hiatus between Southern China and New South 
Wales, and the fourth between the Bhutan Himalayas and the Blue 
Mountains in South-east Australia. But these gaps can be filled 
up by other species that reach Japan and Malaya from the Himalayan 



350 PLANTS, SEEDS, AND CURRENTS 



region, but fall just short of Australia. Thus Sphagnum junghuh- 
nianum is a Himalayan species that has arrived at Japan to the 
north-east and at New Guinea to the south-east after halting in the 
last case on the mountains of Java and Celebes. (On account of 
its convenience the term " Malaya " is applied in this chapter to all 
the region between South-eastern Asia and Australia.) 

Bridging over the Gap in Malaya by the Carices. — The more 
numerous data supplied by Carex enable us to bridge over the gap 
usually presented by Sphagnum in the Malayan region, since one- 
third of the eighteen Asiatic species found in the Australian and 
New Zealand region are there represented. If we look at the twelve 
Carices that jump over the Malayan Archipelago, we find that eight 
are wide-ranging North American and Eurasian species; and, as 
indicative of their capacity to reach as far as they can get, we notice 
that all but one have traversed Eastern Asia and reached Japan, 
four or five of these being recorded from the Himalayas. 

The six Australian and New Zealand Carices that fill up the gap 
in Malaya (C. rara, indica, rafflesiana, maculata, breviculmis, brunnea) 
are purely Asiatic, none being recorded from either Europe or North 
America. They are most at home as denizens of warm latitudes in 
southern and south-eastern Asia ; but they also illustrate in the case of 
three of them (C. rara, breviculmis, brunnea) how the same species of 
Carex from a centre in the Himalayan region can reach Japan in the 
north-east and Australia in the south-east. The distribution of C.indica 
is illustrative of the track pursued by one of these Himalayan species 
in reaching Australia. We can connect its habitat in Sikkim and 
in Northern Australia with records from Assam, the Malay Peninsula, 
Borneo, Java, and New Guinea. The case of C. breviculmis is also 
interesting and suggestive. From an altitude of 10,000 feet in the 
North-west Himalayas it passes across Assam to Tonkin and appears 
on Mount Scratchley in New Guinea at an elevation of 12,200 feet 
before making its way south to South-eastern Australia and New 
Zealand. 

These half a dozen Carices that halt in the Malayan region on their 
way to Australia from South-eastern Asia include, as has been said, 
three Himalayan species ; and in this connection it should be noted 
that several other Himalayan Carices accompany them as far as the 
highlands of Sumatra, Java, and Borneo, but no farther. I have 
made from KiikenthaFs monograph a list of fourteen purely Asiatic 
species (ten Himalayan and four from Southern India and Assam) 
that have had their passage to the south-east arrested in Malaya. 
They were, however, more successful in their passage to the north- 
east, since half of them have reached Japan. But the point to be 
specially noted here is that the Carices from the Himalayan heights 
select similar great altitudes in Malaya. Thus C. filicina and C. 
fusiformis, which have been recorded from elevations of 8000 to 
12,000 feet in the Himalayas, have been collected on Mount Kinabalu 
in Borneo at altitudes of from 9500 to 11,500 feet. So again, 
C. teres, which occurs on the Sikkim Himalayas at an elevation of 
8000 to 9000 feet, has been gathered on the slopes of the volcanic 
mountain of Papandayan in Java. 



DISTRIBUTION OF SPHAGNUM AND CAREX 351 



Comparison of the Sphagnum and Carex Floras of Australia 
and New Zealand. — These remarks on the combined Australian 
and New Zealand region may be supplemented by a reference to 
the separate Sphagnum and Carex floras of the two subregions, as 
exemplified in the table before given. As respects Sphagnum, 
Australia and New Zealand when contrasted present much the same 
degree of endemism. With Carex, however, the New Zealand 
endemism is much more pronounced. As might be expected, the 
Asiatic connections of the Australian Carices are more evident than 
in the case of those of New Zealand; whilst the South American 
connections are more apparent in New Zealand. But it will be 
brought out below that these South American relations, as indicated 
in the table, cannot be taken at their face- value, either for Australia 
or New Zealand. 

The Asiatic Connections of the New Zealand Carices. — 
Of the ten New Zealand species displaying Asiatic connections, seven 
are also known from Australia, viz. C. pyrenaica, stellulata, gaudi- 
chaudiana, breviculmis, brownii, pseudocyperus, and pumila. Three 
of these, the first, second, and sixth, are wide-ranging North American 
and Eurasian species. The others are purely Asiatic, except the 
last (C. pumila), which, though spread over Eastern Asia from 
Manchuria to Hongkong, occurs sporadically in the New World in 
Chile. It is discussed on p. 339. One of the most interesting of 
these seven Carices is C. breviculmis. It is the only one of them that 
breaks its journey from South-eastern Asia to Australia by halting, 
as already observed, on Mount Scratchley in New Guinea at an 
altitude of 12,200 feet above the sea. 

Of the three Asiatic New Zealand species which have not yet been 
found in Australia, Carex diandra, C. lagopina, and C. cederi, the last 
named is recorded from Tasmania; and it seems not unlikely that 
one or more of them will be discovered in the highlands of Eastern 
Australia. All of them seem to pass from Southern Asia to Australia 
without halting in the Malayan region; but one may expect that 
some future explorer of the peaks of Sumatra, Java, and Borneo 
will aid in filling up this gap. Of the three, perhaps C. lagopina 
is the most interesting. This Arctic and Alpine species of North 
America and Eurasia is a characteristic sedge of the Southern Alps 
of New Zealand. The nearest Asiatic locality from which it has 
been recorded lies in the Khasia Hills of Assam. No question of a 
South American origin arises, since New Zealand exhibits its only 
known habitat in the southern hemisphere. Carex diandra has a 
similar distribution in the northern hemisphere; but it does not 
occur in such high latitudes. It exists in both the North and South 
Islands of New Zealand ; but there are great gaps separating it from 
the Eastern Himalayas and Japan, its nearest recorded habitats. 
Carex wderi is another North American and Eurasian species, which, 
however, as already noticed, has a special variety (var. cataracta?) 
peculiar to New Zealand, Tasmania, South Africa, and extra-tropical 
South America. The wide gaps separating New Zealand from the 
nearest Asiatic habitats of the parent species in Kashmir and Japan 
seem at first sight to point to a derivation across the Southern Ocean, 



352 PLANTS, SEEDS, AND CURRENTS 



a view supported by the distribution of the special variety above 
mentioned ; but this subject is further noticed in the next paragraph. 

The South American Connections of New Zealand and 
Australian Carices. — With regard to the apparently greater con- 
nection with South America which is displayed by the New Zealand 
Carices as contrasted with those of Australia, there is this to be said. 
Of the five New Zealand species concerned, two, C. pseudocyperus 
and C. pumila, are Queensland plants, which are found, the first in 
Kashmir and the second in South China, so that it is scarcely requisite 
to look to the southern part of South America for their source. Of 
the other three species, C. darwinii, trifida, and cederi, it has already 
been said that the question of derivation from South America is 
only imminent with respect to the first two, since they are found 
nowhere else than in the New Zealand region and in the southern 
part of South America. Whilst with C. trifida the evidence is in- 
decisive, the probability is that the Chatham Islands received C. 
darwinii from Fuegia. The special variety of C. osderi, which has 
often been mentioned as occurring in New Zealand, South Africa, 
and southern South America, lends support at first sight to the 
trans-oceanic hypothesis; but it is shown that if put at all the 
question should be narrowed down to the issue whether New Zealand 
or South America is its original home, and preference is given to the 
view that each of these regions derived the parent form from the 
northern hemisphere, a corresponding varietal modification subse- 
quently taking place in each region. 

However, to be on the side of safety we will assume that two of 
the fifteen New Zealand species which are found outside that region 
could have been derived from Fuegia. It is different with the three 
species (C. canescens, pseudocyperus, and pumila) that apparently 
connect Australia with southern South America. It has above been 
shown that the two last named probably reached Queensland from 
Asia. As respecting C. canescens, the direct South American con- 
nection is also excluded. It has been found in the mountains of 
South-eastern Australia, though not in New Zealand. Like C. lago- 
pina it is an Arctic and an Alpine species of the northern hemisphere, 
both in America and Eurasia. Just as Fuegia received it from the 
north by the way of the Chilian and Argentine Andes, so Australia 
has received it either from Japan, or from the highlands of Kashmir, 
where it has been found at an altitude of 12,000 feet. Looking 
at all the facts concerned with the streaming of Carices to Australia 
from Asia, it would be hazardous to assume that the mountains of 
New South Wales and Victoria received Carex canescens across the 
breadth of the South Pacific Ocean. On the whole, we may infer 
that whilst New Zealand has derived two of its Carices from South 
America, Australia has received none. 

Similar Role of a Sphagnal Subsection in the Australian 
and New Zealand Region and in Africa. — A supplementary 
remark may here be made on a curious point of resemblance between 
Africa and the Australian and New Zealand region. It has already 
been noticed in the case of the African species of Sphagnum that the 
isolation of the continent is to be associated with the fact that the 



DISTRIBUTION OF SPHAGNUM AND CAREX 358 



majority of species belong to the subsection Subsecunda, which 
possesses no world-ranging species. But this is not only a closed 
subsection for Africa, it is the same for Australia and New Zealand. 
Although it holds one-fourth of the Australian and New Zealand 
species, they are all confined to the region, the species connecting 
it with the outside world belonging to other subsections. 

The Behaviour of Sphagnum and Carex and the Theory of 
Differentiation. — If I were to endeavour to show how the be- 
haviour of the Carices and the Peat-mosses, as discussed in this, 
chapter, fits in with the general theory of differentiation adopted in 
the two preceding chapters, it would be, as briefly expressed, some- 
what to this effect. The Carices represent one of the results of the 
differentiation of a generalised cyperaceous type originally spread 
over the globe; whilst the Cyperi represent another result. These 
two genera largely compose the family, the second being as character- 
istic of warm latitudes as the first is of the cool regions of the north. 
Whilst the distribution of Carex has been mainly determined by the 
divergence of the land-masses from the north and by the secular 
changes of climate, that of Cyperus has been affected to a much less 
degree by these influences. While the tide of the Carices has ebbed 
and flowed in the north, the Cyperi could have reached the common 
focus of dispersal in the Arctic polar area only when exceptionally 
warm conditions reigned at the pole. Cyperus ought to represent 
to some extent the attitude of relative passivity adopted by typical 
plant-groups in the tropics. Its efforts to penetrate the cooler 
regions of the globe have not been very successful ; whilst its sister 
genus, Carex, has only been able to reach the temperate regions of 
the south by halting on the tops of the mountains during its traverse 
of the tropics. 

It is the same with Sphagnum, since it is at home in the moors 
of the north and occurs at high altitudes on the mountains of the 
tropics. But there is evidence, as we learn from Ule as quoted by 
Warnstorf (p. 33), that these plants are adapting themselves to a 
low-level station in the tropics in the coast-plains of South Brazil* 
We seem to know but little of the evolutionary history of a genus 
which was raised by the elder Schimper to the rank of a separate 
family; and it would be useless to evoke a differentiating process 
that would involve the common origin from a generalised type of 
the Peat-mosses, the Mosses proper, and the Liverworts. 

One great lesson supplied by the striking parallelism of two plant- 
types so widely divergent as Carex and Sphagnum is that time has 
long since discounted any especial advantage which the one might 
possess over the other as regards facilities for dispersal. In both 
cases their distribution has been largely determined by the arrange- 
ment of the land-masses and by the alternations of climate. Yet 
such a parallelism would acquire but little importance, if it was 
merely concerned with these two plant-groups. It indicates a 
principle enunciated by Dyer as affecting a host of other plants of 
the north, plants that are often strangely contrasted in almost every- 
thing but their response to the principle of distribution so well 
illustrated in the behaviour of Carex and Sphagnum. 



354 PLANTS, SEEDS, AND CURRENTS 



The last great lesson it presents is shown in the support it gives 
to the views of Bentham and Hooker on plant-distribution. It is 
not easy to be original in any field where they have laboured. Though 
the ground has been " pegged out " by them and others, the " claims " 
are often still unworked. 

Supplementary Note on the means of dispersal of the Carices and 
the Peat-mosses : — 

The Distribution of the Carices by Birds. — It will have been 
noticed in the previous discussion that it has been assumed that species 
of Carex and Sphagnum can follow along the length of the continents 
from the north polar regions to Fuegia, South Africa, and Australia. 
In the case of Carex it is well known that the hard seed-like fruits 
occur in birds' stomachs, and it has been shown that the smaller 
fruits can be carried in dried mud adherent to their feet and legs; 
but the question arises whether birds do actually travel along the 
routes that have been taken by these plants. It has before been 
observed that certain South African Carices must have been derived 
from the northern hemisphere, the possibility of their having come 
•across the ocean from South America, or even from Australia, being 
-excluded by their absence from those regions. This offers a critical 
case, and to some extent we are able to meet it. 

Thus, three instances have lately been recorded of swallows 
captured in Natal and in the Orange Free State, which had been 
*' ringed " in Great Britain (Staffordshire and Ayrshire) nineteen, 
nine, and four months previously (Scotsman, November 8, 1913; 
Times, March 12, 1915). In the Times of the same date reference 
is made to a Sandwich tern, " ringed " in England in July, which 
was found on the Ivory Coast, West Africa, in the following February. 
Then we have the numerous examples of storks marked in East 
Prussia and the neighbouring provinces which were recovered in the 
Transvaal, Natal, Basutoland, and Cape Colony. I am quoting here 
from a paper by A. L. Thomson, who discusses in the Proceedings of 
the Royal Physical Society of Edinburgh for March 1911, the results 
of the German and Hungarian inquiries. Doubtless these facts could 
"he largely increased; but they are sufficient to show that birds do 
actually make periodical migrations from Europe to South Africa. 

The Distribution of the Peat-mosses by the Winds. — It is 
not unlikely that the spores of Sphagnum would be sometimes carried 
in the dried mud adhering to migratory birds; but here the wind 
presents itself as probably a more effective agent. This being so, 
we are at once met with the question whether islands like the Hawaiian 
(that lie in mid-ocean some 2000 miles from the nearest continental 
•coast, would have received their Sphagna through this agency. The 
subject of the transport of seeds and spores by wind is discussed at 
length by Mr. Lloyd Praeger in a recent paper in the Proceedings of 
the Royal Irish Academy (1911), and I have dealt with it in this work in 
connection with the Azores (Chap. XIX). Here it may be stated that, 
as indicated by his experiments on the falling rate of seeds, even 
the dust-like seeds of orchids could not be carried to Hawaii by a 
wind moving fifty miles an hour unless they were raised at the start 



DISTRIBUTION OF SPHAGNUM AND CAREX 355 

to an altitude of fifteen or twenty miles. Although, therefore, this 
would exclude all the flowering plants,even those with plumed seeds, 
the matter assumes a different aspect in the case of the spores of 
cryptogams. Small as it is, the orchid seed may fall fifty times as 
fast through the air as the spore of a mushroom ; and an initial eleva- 
tion of at most 3000 feet would be needed for a successful traverse 
by a mushroom spore of 2000 miles of ocean before a wind blowing 
with a force of fifty miles an hour. This is the maximum altitude ; 
but the average elevation required, as indicated by Buller's falling 
rates given in the table in Chap. XIX, would be only half this amount. 
Though I have no direct data for the Peat-mosses it is not probable 
that their spores would require an initial elevation exceeding the 
average height of a lofty mountain-range like that of the Andes, up 
the slopes of which the ascending currents of air would be able to 
carry cryptogamic spores to a suitable starting-level several thousands 
of feet above the sea. (If the spores of Polytrichum could serve us as 
a guide, the falling rates of which are given in the same table, the 
initial altitude requisite for Sphagnum would not far exceed 1000 
feet.) The occurrence of these up-draughts on the sides of high 
mountains is well known, and the matter is dealt with afterwards. 
In this manner the spores of cryptogams would be brought within 
the influence of the upper air-currents and distributed far and 
wide. 

Summary 

1. On finding that the Sphagnum floras of the eastern and western 
hemispheres become more and more differentiated as one recedes 
from the north polar region, the author turned to the Carices and 
received the same reply. It was at the same time discovered that 
in their distribution both genera reproduce many of the problems 
which the plant-world presents in the case of islands and in the 
floras of the great land-masses of the southern hemisphere. It also 
appeared from the behaviour of Sphagnum that the lower plants 
require a larger area than the higher plants for evoking the full 
effects of the differentiating process, and that in this respect our globe 
may not be large enough for lowly organised plants (pp. 332-4). 

2. A table is given illustrating the effect of the divergence of the 
land-masses from the north on the distribution of Sphagnum and 
Carex. A comparison is then made of their behaviour in the North 
American and Eurasian land-masses, and it is shown for both genera 
that whilst the species common to both gather in the north, those 
separately held congregate in the south. Thus it is indicated for 
Sphagnum that 87 per cent, of the species common to both North 
America and Eurasia are Arctic and Subarctic species. Of the 
species separately held very few are found north of the temperate 
zone. Thus in both the east and the west only 5 or 6 per cent, of 
the species confined to the respective hemispheres occur in Arctic 
or Subarctic latitudes. The Carices tell the same story in both 
hemispheres, the proportion of species which North America holds 
in common with Eurasia being 93 per cent, in the Arctic regions, 
40 per cent, in the Subarctic regions, 24 per cent, in temperate lati- 



356 PLANTS, SEEDS, AND CURRENTS 



tudes, and 11 per cent, in the southern portion of the continent 
(pp. 333-5). 

3. The parallelism between Sphagnum and Car ex is strikingly- 
illustrated in the connections of South America with the rest of the 
globe. In both genera there is the streaming of species from the cold 
latitudes of the north along the line of the Rocky Mountains, across 
the highlands of Central America, and down the Andes, reaching to 
Fuegia (pp. 335-8). 

4. The connections of South America with the Australian and 
New Zealand region may thus be summarised. With both genera a 
few of the species, that have reached the Southern Andes and Fuegia 
from high northern latitudes have been found also either in Australia 
or in New Zealand or in both. But whilst the two species of Sphag- 
num concerned must have been received by each region from northern 
latitudes on the same side of the globe, this can only be inferred for 
three of the six Carices involved. The other three species probably 
crossed the Southern Ocean, one from Fuegia to New Zealand and 
another from Australia or New Zealand to Chile, the data for the 
third being insufficient for the purpose of distinguishing between the 
giver and the recipient (pp. 339-40). 

5. The Car ex and Sphagnum connections between South America 
and Africa are of the slightest. A single South American Sphagnum, 
found also in North America, occurs in Central Africa; whilst a 
single Carex, also North American and Eurasian, connects South 
America with South Africa (pp. 341). 

6. The African Sphagnum and Carex floras are then discussed; 
and here again the behaviour of the two genera offers a striking 
parallel, since they illustrate in a similar way that remarkable isola- 
tion which Africa so often exhibits both in its flora and in its fauna. 
Whilst the European species of Sphagnum have crossed the Mediter- 
ranean only to reach Tunis and Algeria, the Carices from the north 
have in nearly all cases been rolled back by the obstacles presented 
by the Atlas and the Sahara, only a few penetrating to the south of 
the continent (pp. 341-2). 

7. Both genera display a like degree of endemism in Africa, ex- 
clusive of the Mediterranean province, only about 20 per cent, 
of their species occurring outside the continent. But in the case 
of the Peat-mosses (Sphagnum) this cannot be taken at its face- 
value. Whilst the Sphagna connecting South America and the 
Australian region with the outer world range over much of the globe, 
most of the African Peat-mosses that extend beyond the continent, 
as here defined, do not reach further than Madagascar and the 
Mascarene Islands. Africa possesses only one other link with the 
other continents in a solitary North and South American species 
that has apparently a limited distribution in the Lake District. As 
far as the Peat-mosses are concerned, Africa compared with South 
America and Australia is a lonely continent. As regards the African 
Carices, although the proportion of species found outside the region 
is about the same as in Sphagnum, the continent is brought more 
in touch with the outer world by its connections, nearly all the species 
concerned being wide-ranging Eurasian species that may in rare cases 



DISTRIBUTION OF SPHAGNUM AND CAREX 357 



include Australia and even North and South America in their range 
(pp. 342-4). 

8. With both Sphagnum and Carcx more than half of the African 
species belong to the youngest, most vigorous, and largest of the sub- 
divisions of the two genera. Primocarex, the oldest subgenus of the 
Carices and the nearest to the parent-type, fails altogether in Africa. 
The facts indicate that the invasion of Africa by the Carices and the 
Peat-mosses took place during the later stages of the differentiation 
of those genera, and has since been followed by a period of isolation 
extending down to the present time (pp. 344-5). 

9. The sources of the Peat-mosses and Carices of the southern 
part of the African continent are then considered, and it is concluded 
that South Africa has derived all its Sphagna and most of its Carices 
from regions north, it being shown that one of the last named was 
probably brought across the ocean from Patagonia (pp. 345-6). 

10. The parallelism between Sphagnum and Carex presented in 
Africa and South America is also displayed in the Australian and 
New Zealand region, the differences in the behaviour being only in 
degree. Taking first the combined area and its connections with 
South America, we find that the Sphagna concerned and most of the 
Carices could have been derived from northern regions on the same 
side of the globe (p. 347). The connection with South Africa is not 
illustrated by Sphagnum and very doubtfully by two species of 
Carex also found in Asia, which is probably their source (p. 349). 
By far the most important are the Asiatic connections, which are 
treated in detail ; but it may be here observed that all the Sphagna 
and nearly all the Carices which are found outside the limits of the 
combined area occur in Asia. There is no connection either with 
Europe or North America that is not also Asiatic, all the species so 
concerned being widely distributed in the northern hemisphere. 
It is shown that derivation from South Africa and South America 
is altogether excluded for the Peat-mosses and for all but 3 or 4 
per cent, of the Carices, New Zealand having received two species 
from South America and Australia none. Asia, therefore, repre- 
sents the immediate source of the Australian and New Zealand 
Sphagna and Carices (pp. 349-50). 

11. The Sphagnum and Carex floras of Australia and New Zealand 
are then compared ; and it is elicited that whilst the degree of endem- 
ism in each region is apparently similar in the case of Sphagnum, 
it is much more pronounced amongst the New Zealand Carices. 
The respective connections are then discussed (pp. 351-2). 

12. The similarity in the role played by a Sphagnal subsection 
(Suhsecunda) in the African and Australian regions is noted 
(p. 352). 

13. An endeavour is then made to show that the general behaviour 
of the Carices and the Peat-mosses is in agreement with the views 
of distribution adopted in the two preceding chapters. The close 
parallelism between genera so unlike in their rank, so remote from 
each other in their histories, and so different in their modes of dis- 
persal, is a pregnant fact in distribution. It indicates a principle 
affecting a host of other plants of the north that are often strangely 



358 PLANTS, SEEDS, AND CURRENTS 



contrasted in everything but in their compliance with the laws of 
distribution so well illustrated by Car ex and Sphagnum (pp. 353-4). 

14. Amongst subsidiary matters mentioned in connection with the 
Carices and the Peat-mosses are those related to the insular factor 
(p. 343) and the modes of dispersal (p. 354). The insular factor raises 
other considerations than those specially dealt with in this chapter, 
but it is observed in passing that both genera respond in like fashion 
to the differentiating influences that are often intensified in oceanic 
islands. 

Note. — With reference to trans-oceanic dispersal in high southern 
latitudes reference should be made to Note 37 of the Appendix, 
where the distribution of Uncinia, a genus allied to Carecc, is dealt 
with. 



CHAPTER XVII 



THE AZORES 

In the autumn of 1914, after my return from a second sojourn 
in the Azores, it was my privilege to communicate to the Kew 
Bulletin a short general description of the native vegetation of those 
islands as illustrated on the slopes of the mountain of Pico. Here 
it is proposed to considerably extend that paper, using it as a frame- 
work for the author's detailed account of his observations in the 
group. 

It is not at all easy to obtain a general notion of the original flora 
of these islands. Much as has been written on the Azorean plants, 
it is difficult to procure many data concerning the relative frequency, 
the mode of occurrence, and the associations of the native plants, 
except from the earlier writings of Seubert, Hochstetter, Watson, 
Drouet, and others, the later works being mainly concerned wilh 
catalogues of the species. Yet it is on the labours of the systematists 
that we rely for all safe progress in these matters. The monographs 
of Seubert in 1844, of Watson in 1870, and of Trelease in 1897, form 
landmarks in the history of the investigation of the flora. But 
many have laboured to supply the materials, and here we may 
mention Guthnick, the Hochstetter s (father and son), Godman, 
Hunt, C. S. Brown, Sampaio, Carreiro, Machado, and Chaves. 

The Author's Sojourns in the Group. — During his two visits 
to the Azores, from the middle of February to the end of April 1913, 
and from the middle of June to the middle of August 1914, the author 
was principally engaged in investigating the altitudinal ranges of 
the plants. After familiarising himself with the flora during a stay 
of about three weeks on San Miguel, when he ascended the principal 
mountains of the island and enjoyed the privilege, so courteously 
extended to him by the officials of the Municipal Museum at Ponta 
Delgada, of consulting the herbarium, he visited Pico and remained 
on its great mountain from the second week of March to the second 
week of April 1913. During his second sojourn in the group in 1914 
he stayed on the island of Pico from the end of June to the second 
week of August, a period of six weeks, of which the first four were 
passed on the mountain, and the last two in the district of Caes-o- 
Pico and Praynha do Norte, lying off its slopes. The only other 
island examined botanically was Terceira ; but this visit was confined 
to a single ascent of Santa Barbara, its principal summit. His 
intention to spend some time on San Jorge, the only one of the larger 

359 



360 PLANTS, SEEDS, AND CURRENTS 



islands of the group of which the botany is little known, was frustrated 
by the outbreak of the war. 

His Ascents of the Cone of Pico. — Two ascents were made of 
the summit of Pico, 7613 feet above the sea, namely, on April 1, 1913, 
and on July 16, 1914 ; whilst several ascents to altitudes of between 
5000 and 6000 feet were accomplished during both visits on the north, 
east, south, and west sides of the peak, as well as numbers of excursions 
on the lower slopes. A few words may be said here on the best 
plan of exploring the mountain. The usual route to the summit 
from Magdalena by the Serra, past the Lomba (5000 feet above the 
sea), and up the south-west side of the cone, is the worst that could 
be chosen by the botanist, since it does not bring him into contact 
with the upper woods and provides insufficient opportunities of 
examining the upland moors. The constant employment of this 
route has been unfortunate for the botanical exploration of the 
mountain, and largely explains how it came about that it was left 
for the author to be the first to discover one of the most interesting 
plants in the Azorean flora, in the form of Arceuthobium oxycedri, 
a parasite on the Junipers all around the mountain. It also accounts 
for the fact that certain plants, such as the Laurestinus (Viburnum 
tinus), Hydrocotyle vulgaris, etc., which are rarely to be observed 
along this route, were never accredited to Pico until his visit. 

All routes to the peak from the west and south sides meet near the 
Lomba, a prominent hill situated at the south-west angle of the foot 
of the cone proper. It is from this corner that the easiest ascent 
to the summit is made. But the top of the mountain can also be 
reached from the east side. Though more difficult, this ascent was 
effected, as I was told, by a man of San Joao many years ago. 

For the botanist the best plan is to examine the southern slopes 
from San Mattheus, the western slopes from Magdalena, and the 
northern slopes from Bandeiras and Caes-o-Pico; whilst the easiest 
way to explore the eastern, and especially the south-eastern slopes, 
where the upper woods attain their greatest development, is to 
avail oneself of a house used for cheese-making which is situated 
about 2500 feet above the sea between Caes-o-Pico and San Joao. 
The shortest route to the summit is from San Mattheus, and it is 
one that does not involve a night spent on the mountain. By 
starting in the early morning the traveller can reach home the same 
evening after a prolonged stay on the top. Parties of young men 
of San Mattheus make the ascent during the short summer nights, 
and after viewing the sunrise return to their homes in time for their 
day's work. 

Though summer is naturally the most appropriate season, much 
can be done by the botanist on Pico in the winter months, since the 
woods are composed of evergreen shrubs and trees, and the usual 
lower snow-limit encroaches but slightly on the wood- zone. But 
in the winter half of the year, especially when snow lies on the peak, 
it is difficult to procure guides to take one to the top. The bitterly 
cold north winds, the heavy rains, and the prevailing cloud-cap, 
are the chief obstacles at this season. I had to wait for several 
days before I was able to induce my man to complete the last two 



i 



THE AZORES 



361 



thousand feet on April 1. Without informing him of my intention 
to seize the first opportunity when we were exploring the lower 
slopes of gaining the summit, I coaxed him on this occasion to an 
altitude of 6000 feet, and the weather proving fine I completed the 
ascent with the man following very unwillingly behind, the snow 
offering but little difficulty. 

It is the lack of warm clothes that mainly accounts for this un- 
willingness on the part of the Pico islanders to make the ascent 
in winter. Captain Boid observes in the work quoted below that 
in winter the peak is " positively inaccessible on account of the 
snow." This is incorrect. Occasionally in mid- winter a man is 
sent up by a doctor to procure ice for some sick patient in the coast 
towns and villages, but he generally returns with a tale of woe that 
for a long time prevents others from attempting the venture. As a 
fact, the ascent can often be made in winter ; but both the mountain 
and the weather have to be carefully watched, the greatest danger 
to guard against being the dense driving mists, when, as so often 
happens, clouds gather on the higher slopes. Progress then becomes 
impossible, and shepherds who have been tending their sheep have 
perished from exposure. 

I have never heard of any visitor to Pico making the ascent before 
the month of May. Godman attempted it about the second week 
of May after waiting for some days, but the weather prevented his 
succeeding {Natural History of the Azores, p. 15). Though the Bullars 
ascended on May 12 (A Winter in the Azores), that month is usually 
regarded as too early in the year. Indeed, Boid, who was in this 
locality in May 1831, states that he was prevented from ascending 
the peak as he was informed that " the road to the summit was quite 
inaccessible until June " (see his Description of the Azores). 

Sketch "of the Botanical Investigation of the Azores. — 
Apparently, long 'before any systematic investigation "of the flora 
of the Azores, several of its characteristic plants were introduced 
into the gardens of Europe, more particularly those of Portugal 
and England. In southern Portugal Myrica fay a is now " almost 
indigenous " in the mountains of Algarve and in other localities, 
and must have been brought from the Azores long ago, a matter 
referred to in a later page. We learn from Aiton's Hortus Kewensis 
(1789) that this tree, with other plants from these islands, was 
introduced in the Kew Gardens through the agency of Francis Masson 
in 1777 and 1778. Although Masson was one of the first English 
visitors to the Azores to display an active interest in the flora, a 
paper by him in the Philosophical Transactions for 1778 on the 
island of San Miguel contains but little botanical information. In 
the middle of July 1775 George Forster took several excursions on 
the island of Fayal during a stay of four or five days made by the 
Resolution under Captain Cook. He gathered a small collection, 
mainly consisting of weeds of cultivation and of other plants intro- 
duced by man, the list of which is given in the Commentationes 
Societatis Region Scientiarum Gottingensis for 1787 (Vol. IX.). Further 
reference will be made to this list when dealing with the introduced 
plants. It is given in Note 33 of the Appendix. 



/ 



362 PLANTS, SEEDS, AND CURRENTS 

On April 24, 1838, there reached San Miguel a party of scientific 
men, which included Guthnick, a native of Berne, Hochstetter and 
his son Charles, and Gygax, a Swiss mineralogist. From the account 
which Seubert gives in the preface of his Flora Azorica it appears 
that Guthnick, after forming the project of investigating the little- 
known flora of this group, received the advice of De Candolle, and 
that the Hochstetters were his associates in the botanical exploration. 
The party afterwards visited Terceira and Fayal, and here they parted, 
the Hochstetters proceeding to Flores and Corvo in a vessel placed 
at their disposal by Mr. Dabney, the American Consul-general, 
whilst Guthnick during their absence returned to Europe. The 
Hochstetters subsequently visited Pico and ascended the mountain, 
and left the islands in August. I have not been able to discover 
whether Guthnick published an account of his visit to the islands. 
Some of his descriptions of new Azorean species are given in Seubert' s 
work. Among the botanical papers accredited to him in the Royal 
Society Catalogue of Scientific Papers none are concerned with the 
Azores. As regards the Hochstetters, it may be said that their 
collections and notes formed the basis of Seubert' s Flora Azorica 
(1844). They worked out the zones of vegetation on the great 
cone of Pico ; and it is to their labours that the scientific world was 
first indebted for an accurate knowledge of the Azorean native 
flora. Some of their principal results were first published in a sketch 
of the flora entitled " Ubersicht der Flora der azorischen Inseln " by 
Seubert and Hochstetter, which is given in Wiegmann's Archiv fur 
Naturgeschichte, Berlin, 1843, a paper mentioned but not consulted 
by either Watson or Trelease. It contains a large coloured plate 
illustrating the zones of vegetation on the cone of Pico, the plants 
characteristic of each zone being named. But the bulk of the work 
of the Hochstetters was incorporated in Seubert' s Flora Azorica, 
which was issued in the following year, a work which held the field 
until Watson's monograph appeared in 1870 in Godman's Natural 
History of the Azores, and one that still stands foremost as an account 
of the native flora. 

H. C. Watson was the next botanist to visit the group. His stay 
in the islands covered four months, from May to September 1842, 
during which time he occupied a cabin in H.M.S. Styx, then engaged 
in the survey of the archipelago. The exigencies of the survey 
rendered the conditions by no means favourable for his purpose; 
but he obtained collections from Corvo, Flores, Fayal, and Pico. 
His examination of the mountain of Pico was restricted to an ascent 
of the summit with the surveying party from the ship, and to two 
other excursions on the lower slopes; but he expressly states that 
the conditions did not allow him to obtain exact information con- 
cerning the vertical range of the plants on the mountain. This 
regret was expressed in a paper in the botanical publication below 
named for 1843: and it is a pity that in his memoir in Godman's 
work, published many years after, he depreciates the work of his 
predecessors in this respect. In his criticism (p. 114) of Seubert's 
Flora Azorica he gives as an instance of the " guesses that might 
prove only erroneous records " the " alleged ranges of altitudes at 



THE AZORES 



363 



which various of the species are stated to occur; but " (he continues) 
"it is asserted here with some confidence that the stated altitudes 
must too often have been merely rough guesses by somebody not 
sufficiently informed about the true heights of hills and places in the 
Isles." Seubert's data were supplied by Hochstetter and his son, 
and were by no means guesses. As shown in my notes on the Azorean 
plants in Chapter XIX., they conform as a rule very closely with my 
own independent observations, the methods of obtaining the altitudes 
being there stated. 

The results of Watson's investigations were first given in the 
London Journal of Botany, 1843-7, and finally in 1870 in the botanical 
section of Godman's general work. In the last case they were 
greatly extended by a large amount of materials supplied chiefly 
by collections made in 1844-8 by Mr. Carew Hunt, British Consul for 
the Azores, and to a less extent by those made by Godman in 1865. It 
may be added here that the Journal of the Royal Geographical Society 
for 1845 contains a paper on the islands of San Miguel and Santa 
Maria by Mr. Hunt. There is, however, not much in it of botanical 
interest. 

In 1857 there visited these islands Drouet and Morelet, two French 
zoologists, and Hartung, a German geologist, of whom the two first 
specially interested themselves in the botany of the group. Drouet 
and Morelet were more or less associated in their travels, and they 
remained in the islands from April to September. Morelet accom- 
plished the ascent of Pico and made valuable observations on the 
vertical distribution of the plants. Drouet attempted the same 
ascent ; but his strength failed him, and he turned back when about 
half-way up the mountain. Morelet published his notes in his 
lies Azores (L'Histoire Naturelle) in 1860. Drouet was rather more 
ambitious, since he published in 1866 a list of the plants of these 
islands in his Catalogue de la Flore des lies Azores. But, as Watson 
points out (p. 119), his enumeration suffers from defects that were 
to be expected in a work written by one whose chief speciality was 
zoological. Yet with Drouet' s book in his hands the botanist 
visiting these islands for the first time would be well provided, and 
the mistakes arising from lack of familiarity with synonyms and 
" name-changes " would be more than counterbalanced by the 
valuable notes relating to the plants. Hartung, whose work on 
the geology of the islands (Die Azoren, Leipzig, 1860) has long been 
the principal authority on the subject, remained in the group until 
the end of August. He seems to have made but a short examination 
of Pico, and, though he visited all the islands, San Miguel and Terceira 
occupied most of his attention. His book is chiefly of interest to 
us from the observations it contains on the ancient trunks of Juniper 
buried in the volcanic tuffs of San Miguel. He devotes about forty 
pages to the flora, but he depends entirely on Seubert and Watson, 
and in his comparison of the Azorean, Madeiran, and Canarian floras 
he relies principally on Heer. It does not appear that he made many 
observations on the living plants. 

Excluding the Portuguese investigators, to be subsequently 
referred to, the next person to interest himself in the vegetation of 



364 PLANTS, SEEDS, AND CURRENTS 



the Azores was Godman, who, although his special mission was 
concerned with zoology, made extensive plant collections during 
his stay in the group, March to May 1865. These materials were in 
part worked up by Watson in his monograph in Godman' s book on 
the natural history of the islands. In 1894 Mr. C. S. Brown made 
considerable collections, chiefly on Fayal, Pico, and San Miguel. 
They were utilised by Trelease in the work to be immediately men- 
tioned. Three months in the summer of 1894 and a shorter period 
in 1896 were occupied by Trelease, Director of the Missouri Botanical 
Garden, in making collections in these islands. They were worked 
up by him and the results incorporated with those of his predecessors 
in his Botanical Observations in the Azores, published in 1897 in the 
Eighth Report of the Missouri Botanical Garden. The general 
remarks are limited ; but as a catalogue of the plants this monograph 
is the most complete and authoritative of the works on the Azorean 
flora that have been published up to the date of my writing. In 
March 1909, G. C. Druce made a brief stay on San Miguel, which 
supplied materials for short papers in the Journal of Botany for 
January 1911, and in the Chemist and Druggist. 

The last to be mentioned, but not the least important of the in- 
vestigators of the Azorean flora, are those resident Portuguese 
gentlemen who in bygone and in recent times made numerous private 
collections and built up the herbarium in the Municipal Museum 
at Ponta Delgada. Much of the work of Dr. Bruno T. Carreiro, 
Dr. C. Maehado, Dr. J. A. N. Sampaio, and others is utilised by 
Trelease in his monograph; but there must be many whose labours 
have contributed to our knowledge of the plants of these islands, 
though their names are no longer remembered. An account of those 
of the earlier Portuguese residents, who in the long years since the 
occupation of the islands have paid attention to the plants, would 
come fitly from the pen of a Portuguese botanist. In 1852 there 
was published at Lisbon a list of plants introduced into the Botanic 
Garden of the Medical School of that city from various parts of the 
world, the authors of which were B. A. Gomes and C. M. F. da Beirao 
(Catalogus Plantarum Horti Botanici Medico-Chirurgicce Scholar 
Olisiponensis). Azorean plants are here included. In conclusion 
one may observe that in addition to his special studies on the general 
zoology and fossil diatoms of the group, Colonel F. A. Chaves, the 
head of the Meteorological Service of the Azores, has done much 
not only in collecting flowering plants, but in assisting botanists 
visiting the islands. 

The Heights of the Azores. — The great volcanic cone of Pico, 
7613 feet in altitude, is by far the highest mountain in the group, 
none of the other islands attaining half its height. There are eight 
other islands, and it is very remarkable that the three largest and 
most elevated of them have practically the same elevation, San 
Miguel 3570 feet, Terceira 3500 feet, and San Jorge 3498 feet ; whilst 
the two islands next in size, Fayal and Flores, are not much lower, 
their respective heights being 3351 and 3087 feet. This is a physical 
feature of importance, since Pico loses the advantage of its much 
greater elevation on account of the predominance of lava and cinders 



THE AZORES 



365 



in its upper portion ; and for purposes of comparison, as concerning 
the average soil-conditions suitable for vegetation, we may regard 
only its lower 4000 or 4500 feet. Taking the whole island of Pico, 
the same rule applies, since with the exception of the peak none of 
the other mountains exceed 3500 feet in height. It is true that 
Pico Topo, lying behind Lagens, is credited in the Admiralty chart 
and in the accompanying " Sailing Directions " with an altitude 
of 5357 feet; but there is an error here, the true elevation, as the 
writer ascertained by aneroid, being about 3300 feet. This mistake 
doubtless dates back to the time of the survey of the archipelago 
by Captain Vidal, 1842-4. The author spent some days in the 
vicinity of this mountain, which does not exceed the average height 
of the peaks of this part of the island, the great cone towering far 
above them all. He learned from Colonel Chaves that up to 1914 
the Admiralty chart of the island was the only available map. (In 
the latest issue of this chart (No. 1855) the correction has since 
been made, the height of Pico Topo being there reduced to 3357 feet, 
as indicated in the map of the island accompanying this work.) 

Comparison of the Conditions of Forest-Growth in the 
Azores, Madeira, and the Canaries. — From what has been said 
above we should be safe in assuming that the soil- conditions for 
typical forest growth in the Azores, as a whole, cease usually at 
altitudes between 3000 and 4000 feet. It would seem from the early 
accounts of Madeira that the original forests must have extended 
nearly to the summit of the island, and we will take their average 
limits as between 5000 and 6000 feet. In the Canaries, as illustrated 
by Teneriffe, this limit would be generally about 7000 feet. After 
applying to these values for the three Macaronesian groups the 
correction for the difference in latitude and for the associated differ- 
ences in climate, we should expect to find in the Azores only the 
Canarian forest vegetation of between 2000 and 5000 feet, or, in 
other words, the evergreen shrubs and trees of the Laurel-belt. We 
could scarcely look for more, since the higher Pine-belt of Teneriffe 
could not exist on the lava and cinders of the higher levels of the 
cone of Pico ; whilst the lower Canarian coast-belt with all its strange 
African plants would be unrepresented for want of the warm climatic 
conditions. In Madeira, intermediate in latitude and in climate 
between the other two groups, we should expect to find an inter- 
mediate condition of things. The lower African zone, so well de- 
veloped in the Canary Islands and absent from the Azores, ought to 
be considerably restricted in Madeira; and, since this island barely 
emerges from the cloud-belt, its forest vegetation of the Canarian 
type might be expected, subject to soil-conditions, to reach the 
summit. In this correlation of the three floras, the writer, as far 
as the Azores and the Canaries are concerned, was long ago fore- 
stalled by Hochstetter and Morelet. Its significance will be made 
more apparent in a later page. 

The General Profile of the Cone of Pico. — The characteristic 
appearance of the great cone of Pico is that of a mountain rising 
with easy slopes for its lower two-thirds, and then ascending pre- 
cipitously to the summit. Except on the southern side it rises 



366 PLANTS, SEEDS, AND CURRENTS 



gently up to between 2000 and 2500 feet; after which there is a 
steeper gradient to between 4500 and 5000 feet ; and then it ascends 
rapidly to the top. Yet it would be difficult to find a lofty volcanic 
mountain rising from the sea with such a steep slope as is presented 
by the great mountain on its south side. It attains its maximum 
elevation of 7613 feet at a distance of 2*42 geographical miles from 
the coast, which represents an average angle of slope of about 27°. 
Mr. Samler Brown rightly says in his guide-book to these islands 
(edit. 1905, p. 7) that it rises more abruptly from the sea than the 
Peak of Teneriffe. Taking the shortest distance from the coast 
at seven and a half miles and the altitude at 12,180 feet, the Peak 
of Teneriffe rises from the sea on its north side at an average angle 
of about 15°. 

There is some excuse for those who have coasted along the south 
side of the island of Pico, or who have lived for weeks, as I have done, 
on the south coast under the shadow of the peak, if at times they 
carry away the exaggerated impression of a great cone rising in 
places almost sheer from the sea. There lies before me a chart of 
the Azores by Wm. Heather, dated 1822, drawn, revised, and cor- 
rected by J. W. Norie, hydrographer. In a profile sketch of the 
peak, bearing E. 3° S. by compass, the mountain is represented as 
pinnacle-formed and rising from the sea to its summit at an angle 
of about 60°. This, of course, is very far from being the case, as 
may be seen from the profile sketches given in the Admiralty chart 
from Captain Vidal's survey in 1842-4. Yet, as will now be shown, 
there is a tremendous drop in a limited region on the southern 
slopes. 

The Bluffs of the Ribiera Grande. — Due south of the peak 
and opposite the coast villages of Praynha do Sud and Terra do Pao, 
the mountain in its lower half drops about 3000 feet in a thousand 
yards, giving rise for a mile or two to a line of huge bluffs, the pre- 
cipitous faces of which are deeply scored by gorges and gulleys 
forming dry river-beds, the largest of them being known as the Ribiera 
Grande. Their steep sides, carved out into spurs and buttresses, 
are usually well wooded, except in the gulleys and gorges, and they 
terminate abruptly in the low and narrow strip of coast on which 
the two villages lie. These bluffs constitute the most precipitous 
portion of the lower slopes of the mountain and present one of its 
chief spectacular features. The winding paths used by the shepherds 
tending their sheep ascend what looks from a distance like an im- 
possible precipice. Yet with a guide the ascent, though tedious, 
is not difficult. Tiny white specks, which dot the upper declivities, 
mark the sheep, and bring home to the climber the great height of 
the bluffs. 

Above the higher edge of the bluffs the steep upper slopes of the 
mountain are streaked by " slides " of boulders and loose blocks 
of lava, where no vegetation obtains a hold, localities that my guides 
were very unwilling to approach. Not infrequently a huge boulder 
is set in motion, and rolling down the slide it leaps over the upper 
edge of the bluffs, and bounding down their precipitous sides at 
tremendous speed, ultimately plunges into some field or garden at 



THE AZORES 



367 



their base and comes to rest. To the people of the coast villages, 
especially of that of Terra do Pao, which lies immediately beneath 
the bluffs, the bombardment by boulders is a matter to be reckoned 
with. They pointed out some to me which they declared had come 
from the upper slopes of the peak. One of them was about three feet 
high, and I was told that this size may be much exceeded. These rock- 
masses, after leaping and bounding for at least 4000 or 5000 feet 
down the steep mountain sides, sometimes come crashing down 
into the precincts of the village in the middle of the night. 

The Extent of the Vegetation on the Mountain of Pico. — 
The impression formed at a distance that the lower two-thirds of 
the mountain are vegetated and that the lava slopes of the upper 
third are barren, is verified only in a relative sense when the observer 
ascends the mountain. Godman (p. 15) remarks that " in winter 
the extreme cone is frequently covered with a thin layer of snow, 
and is destitute of vegetation with the exception of a few lichens." 
Ogilvie-Grant, speaking of the Magdalena side of the mountain, 
states that on the higher slopes " desolation and lava covered with 
grey lichen and moss hold undisputed sway " (Nov. Zool., Jan. 1905). 
Impressions of this kind are often acquired by those who have not 
made the complete ascent. 

The lower slopes are generally well vegetated up to altitudes of 
4500 to 5000 feet, moor and grass land predominating in their higher 
levels, that is, above 2000 feet. Woods are well developed in places, 
the lower woods on the western side and the upper woods on the 
south-eastern side. On the north-west side there is an almost 
continuous band of wood, which extends from the vicinity of Ban- 
deiras, about 400 feet above the sea, right up the mountain slopes 
to over 5000 feet, where the trees and shrubs are dwarfed. The 
woods are essentially formed by evergreen shrubs and trees; but 
on account of the persistent agency of the woodcutter through 
centuries the trees, except when specially preserved, rarely exceed 
twenty feet in height, and are usually not more than fifteen or sixteen 
feet. Dwarfing of the trees and shrubs begins as a rule at about 
4000 feet as the effect of deficient soil and of exposure to the prevailing 
strong winds; but it is likely that in the early times forests of 
considerable height existed at this altitude. 

Above the level of 5000 feet the sparse vegetation of the pre- 
cipitous upper third of the mountain presents a great contrast to 
the grassy and wooded slopes below. On the crumbling lava and 
on the beds of cinders and coarse ashes that form the surface plants 
for the most part obtain a scanty hold. It is true, however, that 
dwarfed trees and shrubs climb the steep slopes for a few hundred 
feet, the scrub failing at levels short of 6000 feet; but above that 
height vegetation is sparse, and the plants become scarcer and scarcer 
as one nears the summit, about half a dozen species reaching in 
much diminished numbers the terminal crater and its small cone. 

The Zones of Vegetation on the Mountain of Pico. — When 
the writer visited Pico with the object of determining the altitudinal 
arrangement of the plants, he was only acquainted with Watson's 
and Trelease's monographs, issued respectively in 1870 and 1897. 



368 PLANTS, SEEDS, AND CURRENTS 



In the first-named work the subject is hardly mentioned, whilst 
in the second it is not alluded to. After he had made his study, 
he was surprised to find that excellent accounts of the vertical 
distribution of plants on the mountain are to be found in the writings 
of Hochstetter (1843), Seubert (1844), and Morelet (1860), and that 
Drouet (1866) gave many details of importance. However, it is 
to the Hochstetters that we are most indebted for information on 
the subject. It was with mingled feelings of satisfaction and dis- 
appointment that the writer discovered that his main Tesults were 
in close agreement with those of the German investigators and of 
their later French fellow- workers in this field. 

In the vertical range of the plants there are few material differences 
between the writer's results and those of the previous investigators. 
In the actual arrangement of the zones the differences are also few, 
and in the main the suggested zones either confirm or amplify the 
writer's own arrangement. 

The zones on Pico, as first described in the conjoint paper by the 
elder Hochstetter and Seubert in Wiegmann's Archiv (1843), were as 
follows : — 

I. The cultivated or Mediterranean zone, extending from the coast 
to an altitude of 1500 feet and characterised by Mediterranean and 
European cultivated plants, weeds, and shore plants. 

II. The Canarian zone, or belt of the Laurel woods, extending 
from 1500 to 2500 feet. 

III. The Azorean zone, or region of shrubs, 2500 to 4500 feet, 
where many of the species peculiar to the Azores occur. 

IV. The bush or scrub region, 4500 to 5000 feet. 

V. The peak region, above 5000 feet to the summit (7600) feet. 

There are one or two conspicuous defects in this arrangement. 
In the first place, the Canarian zone extends considerably above 
2500 feet. Then, any scheme that ignores the vegetation of the 
upland moors, so prominent a feature on the slopes of the mountain, 
between 2000 and 4000 feet, would be incomplete. The data, again, 
scarcely justify our regarding the region between 2500 and 4500 
feet as characterised principally by shrubs, or as being the special 
home of peculiar Azorean plants. The coast, the lower woods, 
and the upland moors, all present some of these endemic plants, 
which number only about thirty in all, several of them having been 
not yet recorded from Pico. 

In Seubert's Flora Azorica, published in the following year (1844), 
zones II. and III. are named respectively, the regions of the lower 
and the upper mountain woods, a correction which makes the arrange- 
ment closely similar to the one independently adopted by the present 
writer, the characteristic plants of each zone being in close correspond- 
ence. Here again, however, the belt of the upland moors is not 
recognised. The arrangement, as given by Seubert, is based on 
Hochstetter' s notes, and is as below given. 

I. Region of cultivation, coast to 1500 feet. 

II. Lower mountain woods, 1500 to 2500 feet. 



THE AZORES 



369 



III. Upper mountain woods, 2500 to 4500 feet. 

IV. Region of bushes, 4500 to 5200 feet. 

V. Highest zone, above 5200 feet, mostly lava, etc. 

Morelet, in his work on the natural history of the Azores (1860), 
adopts three zones of vegetation for the islands generally, namely :— 

I. The zone of cultivation to 500 metres (1640 feet). 

II. The middle zone, or the zone of woods, extending up to 1500 
metres (4920 feet), and corresponding in the laurels and other ever- 
green trees and shrubs to the laurel-belt of the Canary Islands. 

III. The superior zone, 1500 metres to the summit. Here the trees 
and shrubs become less vigorous and give place to the pastures and 
the heaths. Only represented on Pico. 

This is a good arrangement, though it is an error to place the 
pastures in the third zone, the upland moors, to which he evidently 
refers, belonging to his second zone. 

The Zones of Vegetation on the Mountain of Pico as De- 
termined by the Author. — We now come to the zones adopted 
by the writer. As regards their limits there is a very close similarity 
with those framed by Seubert from the notes of the Hochstetters 
and given in his Flora Azorica. They were determined under the 
belief that the present writer was the first to make this inquiry, and 
their close correspondence with those adopted by Seubert enables 
him to tread on firm ground in this matter. Before the occupation 
of the islands the lower woods must have usually extended to the 
coast, as they do now in places. Since it is with the native flora 
and the original condition of the island that we are here concerned, 
the region of cultivation is omitted and the belt of the upland moors 
has been added. The list of plants, below given as most character- 
istic of each zone, include all those named for the same zone by 
Seubert and Hochstetter, with the addition of others. 

I. The Lower Woods or the Faya zone, extending from the coast 
to between 2000 and 2500 feet above the sea. The most abundant trees 
are Myricafaya. Erica azorica, and Laurus canariensis (Per sea azorica). 
Next in order of frequency come Ilex perado, Rhamnus latifolius, 
Persea indica, and Picconia excelsa, the last two being now rare. 
Taxus baccata, at present almost extinct, found its home in the higher 
levels of this zone. The most characteristic shrubs in their order 
of frequency would be Myrsine africana, Vaccinium cylindraceum, 
Hypericum foliosum, and Viburnum tinus. Hedera canariensis and 
a species of Smilax represent the climbers, and Rubus fruticosus 
occurs in the undergrowth. Osmunda regalis is the most conspicuous 
of the ferns. Doubtless in the original forests this zone was divided 
into two sub-zones by the distribution of the two laurels, Laurus 
canariensis (Persea azorica) characterising the upper half and Persea 
indica the lower half. 

II. The Upper Woods or the Juniper zone, between 2000 and 4500 
feet for the woods proper and from 4500 to 5500 feet for the scrub. 
There is often a neutral area between 2000 and 3000 feet, where 

B B 



370 PLANTS, SEEDS, AND CURRENTS 



the plants of the Faya and Juniper zones intermingle ; but as a rule 
the Juniper begins where the Faya ends. The three most distinctive 
trees and shrubs of this zone are in their order of frequency, Juniperus 
oxycedrus (var. brevifolia), Daphne laureola, and Euphorbia stygiana, 
the Tree-Euphorbia. But Erica azorica (Tree-Heath), Laurus 
canariensis, Myrsine africana, Ilex perado, and Vaccinium cylin- 
draceum, all of the lower woods, are here also abundant ; and charac- 
teristic among the ferns are Dicksonia culcita and Acrostichum 
squamosum, with Woodwardia radicans on the sides of the gulleys. 
A common parasite on the Juniper trees is Arceuthobium oxycedri. 
In the original forests Taxus baccata thrived in the lower levels of 
this zone. 

III. The Calluna, Menziesia, and Thymus zone, 5500 feet to the 
summit (7600 feet), the cone proper. Mats of Calluna vulgaris and 
of Thymus serpyllum (var. angustifolius) and tufts of Menziesia 
polifolia predominate on these scantily vegetated steep slopes of 
lava and cinders. Polygala vulgaris also occurs with one or two 
grasses, such as Agrostis castellana. 

There is a close agreement between my predecessors and myself 
as to the five plants that exist in the higher levels of the peak. All 
of us, Hochstetter in 1838, Watson in 1842, Morelet in 1857, and the 
writer in 1913 and 1914, record the Ling {Calluna vulgaris) and the 
Thyme, and three of us the Polygala, the Menziesia, and the Agrostis. 
The strangest reference is to the Polygala, which owes its occurrence 
at this elevation to the protection it finds in the beds of Ling. A 
solitary specimen was found by Watson in this locality (Lond. Journ. 
Bot., II., 394) ; but the plant is frequent enough to be regarded as 
one of the characteristic terminal species, and as such it was rightly 
viewed by Seubert and Hochstetter. 

Though the number of terminal species does not seem to have 
increased in the interval between 1838 and 1914, it is likely that the 
Ling, the Thyme, and the Menziesia have considerably extended 
the area occupied by them on the level shoulder on the south side 
of the mountain between 6500 and 7000 feet above the sea. With 
the exception of Polygala vulgaris, all the plants of the highest levels 
on Pico are widely distributed over the group. They are not neces- 
sarily summit plants, but have found a home in the highest levels 
because they alone of the plants of the lower levels, more especially 
of the moors, have been able to establish themselves there. Polygala 
vulgaris has been only found on the island of Pico, where it was collected 
on and near the summit of the great mountain by Hochstetter in 1838, 
by Watson in 1842, and by myself in 1914 ; but as below observed 
I found it also on the moors below, as well as in those of the lake 
district to the eastward. Agrostis castellana, as we learn from 
Trelease, is a polymorphous Spanish species that is widely distributed 
in the Azores, being the most abundant of the native grasses. It is 
important to note that all the plants that have reached the top of 
the great cone of Pico have climbed the slopes from the moors below. 
There is no peculiar summit flora. 

IV. The Upland Moors, 2000 to 4000 feet. This zone has been 
formed at the expense of the Juniper zone around much of the moun- 



THE AZORES 



371 



tain. Though doubtless greatly extended by the destruction of 
the forests since the discovery of the islands, the moors have probably 
always formed a conspicuous feature of the mountain of Pico around 
the base of the steep-sided central cone. Without differentiating 
here between the drier and wetter areas, the most striking features 
are the bracken (Pteris aquilina), the large tussocks of Polytrichum, 
and the beds of Sphagnum. Their general characters are often 
those of a Devonshire moor, as on Dartmoor; and most of the 
characteristic species exist in both regions. Amongst the most 
frequent flowering plants are Anagallis tenella, Calluna vulgaris, 
Erythrcea massoni, Hydrocotyle vulgaris, Luzula purpureo-splendens, 
Lysimachia nemorum (var. azorica), Menziesia polifolia, Polygala 
vulgaris, Potentilla tormentilla, Sibthorpia europcea, Thymus serpyllum 
(var. angustifolius), Viola palustris, and among the sedges, Car ex 
flava. Lycopodium selago is common, and Blechnum spicant also 
occurs. Water-holes exist in the more boggy ground, and around 
the edges and in the water of these pools grow Callitriche aquatica, 
Carex stellulata, Littorella lacustris, Peplis portula, Potamogeton 
polygonifolius, Scirpus fluitans, S. multicaulis, etc. 

The Prevailing Climatic Conditions on the Upper Slopes 
of the Mountain of Pico. — With regard to this point it may be 
stated that the cloud-belt or rainy zone, 2000 to 5000 feet, corresponds 
roughly to the Juniper zone and to the belt of the upland moors. 
The " region of clouds," as Watson terms it, is suggestively described 
by him as the region of boreal and marsh plants (Loud. Journ. Bot., 
II., 394). With reference to the higher levels between 6000 feet and 
the summit (7600 feet), although the nature of the surface of crum- 
bling lava and cinders would primarily determine the type of plants 
adapted for growing on steep slopes of this character, the choice 
would be further restricted to plants capable of withstanding in 
such an exposed situation the relatively dry atmosphere, the fierce 
rays of the sun in summer, the frost and snow of winter, and the 
stormy winds that buffet these heights during much of the year. 

Whilst the rainfall would be much less on the high levels than in 
the cloud-invested Juniper zone and upland moors below, its de- 
ficiency would be partly compensated for by the heavy dews. The 
amount of sunshine must be considerably greater here than in the 
zones of the woods below. The mere concealment of the peak by 
clouds, when viewed from the coast, by no means always implies 
that the summit is cloud-capt. Not infrequently, when the writer 
had reached the upper limit of the cloud-belt through a driving 
wet mist, he found the upper third of the mountain exposed under 
a clear sky to the full glare of the sun and rising out of a billowy 
sea of clouds of dazzling whiteness, like an island in the midst of 
Arctic snows. 

Although the daily range of temperature would be greater, it is 
very probable that the monthly means of the temperature of the air 
in the shade on the higher slopes of the mountain would approximate 
those for the elevated region of Dartmoor in the south-west of England, 
between 1500 and 2000 feet above the sea, a range, let us suppose, of 
from 33° in January to about 58° Fahr. in July. Snow comes and 



372 PLANTS, SEEDS, AND CURRENTS 



goes on the peak at intervals during the winter and may lie for 
some time; but it is rarely of any great depth except in the drifts. 
As a rule it disappears finally during May. Godman (p. 10) speaks 
of the snowy top of Pico peeping out from the clouds in the last 
week of April (1865). The statement of Captain Boid (pp. 307-9) 
that snow lies on the mountain nearly eight months of the year 
gives an exaggerated notion of the permanency of the snow-cap on 
Pico. Watson observes that snow may lie under the shade of rocks, 
and (one may add) in cracks and fissures, until May, but no longer. 
He states that six weeks before his ascent on July 1 Mr. Dabney 
had sent a party up to procure snow for a sick friend, " and they 
got some " (Lond. Journ. Bot., II., 394). 

The lower limit of the snow is generally about 4000 feet; and in 
this connection it should be noted that on the summits of the other 
large islands, all of which reach a height of about 3500 feet above 
the sea, snow rarely lies. It is always winter for the people of the 
Western Azores, whilst Pico wears its white cap. During the writer's 
stay on the mountain, from the second week of March to the second 
week of April 1913, snow fell on at least three occasions, and for 
most of the time the peak was white with it. Different ascents 
were made up the snow-covered slopes, and in one of them (April 1) 
he gained the summit. 

General Account of the Vegetation of the Mountain of 
Pico. — Coming to a general account of the vegetation of this great 
volcanic cone, and reversing the customary order of description, we 
will imagine a botanist who, after alighting on the top of the mountain, 
descends to the coast. Upon the summit, not only at the borders of 
the small crater, but also on the sides of its little cone (200 feet in 
height), he would observe in the crevices of the bare lava surfaces 
small stunted growths, only a few inches high, of Calluna vulgaris 
and Menziesia polifolia, with small patches of Thymus serpyllum 
(var. angustifolius), and here and there a tuft of Agrostis castellana. 
Proceeding to descend the lava slopes on the south side he would 
very soon notice specimens of Poly gala vulgaris growing for protection 
in the patches of Ling (Calluna vulgaris). He quickly reaches the 
shoulder of the mountain, a more or less level stretch of lava and 
\Mapilli," 6500 to 7000 feet above the sea, where the Ling and the 
Thyme grow in dense mat-like beds, almost carpeting the surface 
in places, the first named only a few inches high and scarcely higher 
than the Thyme beds. In the middle of July the Ling shows only 
the evidence of the last season's flowering and fruiting, whilst the 
Thyme beds present a mass of bloom. It is on this shoulder of the 
mountain that St. Dabeoc's Heath (Menziesia polifolia) is most 
abundant, and flowers copiously in July. 

[The above description applies to the plants of the summit as 
observed by the writer in the middle of July. When he ascended 
to the top on April 1 of the previous year, the peak was largely covered 
with snow ; but the beds of Ling and Thyme were easily recognised, 
the former plant displaying the bleached sepals of the last season's 
flowering and the latter retaining in abundance the empty fruiting 
calices.] 



THE AZORES 



373 



From the edge of the shoulder one looks down a precipitous slope 
of lava-flows, loose stones, and ashes, covered in places by large 
patches of the Ling, Thyme, and St. Dabeoc's Heath. One instinc- 
tively treads on the mats of Ling and Thyme, since they give a 
firmer foothold during the steep descent. There are few other 
flowering plants, except the half a dozen above named, that grow on 
these arid slopes above 6000 feet. 

Very rarely one comes upon some straggler from the woods below 
growing from seeds dropped by birds in the crevices of a bare lava- 
cliff. Situated far above the ordinary upper limit of the rain-belt, 
exposed to the frosts of winter, and unprotected against the in- 
tensity of the sun's rays in summer, such a plant has a hard struggle 
to hold its own. It was under such conditions, at an altitude of 
6300 feet, that the writer found in the middle of July a few scattered 
individuals of the Azorean Holly (Ilex per ado). Though they were 
scarcely over a foot in height, their thick woody stocks indicated 
that they had been established for some years. They were in bloom ; 
and it was interesting to notice how the axillary flowers were protected 
against the scorching heat of the sun's rays by the raising of the leaves, 
which had assumed the vertical position and lay with appressed 
faces close to the stem. The expanding terminal leaf-buds were 
shielded by the same device ; but more often than not it had proved 
to be ineffectual, and the buds were blackened and dead. 

Our botanist has now descended to an altitude of about 6000 feet. 
Before he gets off the steep upper-third of the mountain on to the 
wooded and grassy slopes of gentler gradient below, he has yet to 
clamber down another thousand or fifteen hundred feet over old 
lava-flows, beds of cinders, and loose stones and boulders that when 
displaced bound for hundreds of feet down the mountain's side. 
But, as he descends, the conditions become a little more favourable 
for plant growth. For a minute or two a driving mist envelopes 
him and shuts all out from view. He has been in a wisp of cloud 
and is approaching the upper limit of the rain-belt. 

Should he descend on the western side he will make but few 
additions to his list of plants, until, at a level of about 5500 feet, 
he comes upon the outposts of the woods in the form of stunted 
bushes of the Tree-Heath (Erica azorica). On the eastern slopes 
of the mountain, where for some reason more humid conditions 
prevail, as soon as he passes below 6000 feet he will find that the 
beds of Ling (Calluna vulgaris) afford protection to a variety of 
different plants. On these wind-swept slopes the Ling beds are 
only four or five inches high ; and in them nestle dwarfed specimens 
of Juniperus oxycedrus, flowering and fruiting, though not over 
six inches in height, as freely as the trees of ten and twelve feet in 
the woods below. On exposed peaks in this group, as may be 
observed on the summits of San Miguel, Terceira, etc., one often 
finds a dense spreading growth of stunted Junipers rising only two 
feet from the ground, a feature also observed and well described by 
Watson (p. 224); but nowhere did the present writer notice the 
dwarfing process so pronounced as in the case of these tiny Junipers 
fruiting in the Ling beds on the bleak heights of the great mountain 



374 PLANTS, SEEDS, AND CURRENTS 



of Pico. Amongst the other flowering plants that find a sanctuary 
in these Calluna beds at altitudes of 5000 to 6000 feet are delicate 
herbaceous plants, like Polygala vulgaris, Erythrcea massoni, and 
Lysimachia nemorum, and a hardy plant like V actinium cylindraceum, 
which, however, instead of growing nine or ten feet high, as in the 
woods, is here reduced to five or six inches. Of the ferns and lycopods 
that are able to hold their own at these high levels of 5000 to 6000 
feet, Blechnum spicant takes refuge in the Ling beds, whilst Lyco- 
podium selago seeks a shelter in the hollows of the lava. 

The impression one forms while descending these steep lava 
slopes of the upper-third of the mountain is that many of the plants 
characteristic of the lower levels would reach the summit, if the 
soil- conditions allowed it. This was also the opinion of Morelet, 
the French zoologist, who ascribed the penury of the higher levels 
to the nature of the surface and to the steep angle of the slopes. 
The repressive influence of the fierce winds that blow around these 
heights during much of the year would be mainly found in the dwarf- 
ing of the trees and shrubs. That several of the plants which are 
at home in the upper woods between 2000 and 4000 feet can grow 
at levels between 5000 and 6000 feet is shown in their readiness to 
seek shelter at these heights in the small craters and gulches, in 
the broken-down lava caverns, and in the numerous fissures, cracks, 
and holes. Here we find the Tree-Euphorbia (E. stygiana), the 
Azorean Holly (Ilex perado), Daphne laureola, Myrsine africana, 
Laurus canariensis, etc., species that are not to be seen on the wind- 
swept slopes near-by; whilst the Juniper and V actinium may be 
observed growing four or five feet high in a pit and only four or five 
inches high when exposed at its borders. 

But apart from these sanctuaries on the higher slopes for the more 
adventurous plants of the woods below, stunted specimens of the 
Tree-Heath (Erica azorica), which form the outposts of the woods, 
sometimes ascend, as already observed, the lower slopes of the steep 
upper-third of the mountain to between 5500 and 6000 feet. When 
we get off these steep slopes at a level of from 4500 to 5000 feet, 
the soil- conditions become more favourable. Here the Tree-Heath 
begins to assert its arborescent habit, and it is associated with Juniper 
trees of fair size, the Juniper growing well on suitable ground at 
these altitudes. 

We now enter the cloud-belt, or rainy zone, which in its limits 
of 2000 to 5000 feet rudely corresponds to the upper mountain 
woods. Amongst the trees, Erica azorica is often predominant, 
attaining its greatest development in the middle of the belt and grow- 
ing, when left undisturbed, to a height of fifteen, eighteen, and even 
twenty feet ; while in the open woodland bushes of Calluna vulgaris 
may be nearly as abundant. It is between 3000 and 4000 feet that 
the upper woods display their best growth, and this is well seen 
on the south-east slopes of the mountain. Although on account 
of the woodcutter's destructive influence, exercised through cen- 
turies, the wood is small, the height of the trees not usually exceeding 
fifteen or sixteen feet, several of them when left alone can attain, 
as below shown, twice this height. Among the other characteristic 



THE AZORES 



375 



trees and shrubs of the upper woods are Laurus canariensis, Myrsine 
africana, Ilex perado, Daphne laureola, Vaccinium cylindraceum, 
etc.; and here thrive as solitary specimens, or in twos and threes, 
the Tree-Euphorbias (E. stygiana). 

Indications of the prevailing humidity in the upper woods are 
displayed in the filmy ferns (Hymenophyllum tunbridgense) growing 
on the trunks of the large Junipers and Tree-Heaths. In the rank 
undergrowth flourish ferns like Dicksonia culcita, Acrostichum 
squamosum, and the Bracken (Pteris aquilina), lycopods like Lycopo- 
dium complanatum, and flowering plants, such as the beautiful 
Euphrasia grandiflora and Carices, among which we may mention 
Carex stellulata. Woodivardia radicans is conspicuous amongst the 
ferns that drape the sides of the gulleys; and clothing the moist 
and shady banks of the small stream-channels are the fronds of 
Trichomanes speciosum. Covering the walls of the lava caverns are 
Selaginello? and Hepaticae. 

When long undisturbed these upper mountain woods form dense 
thickets difficult to penetrate. Here thrives on the branches and 
trunks of the Juniper trees the Loranth, Arceuthobium oxycedri, 
a parasite that grows commonly on these trees all round the slopes 
of this mountain at elevations of from 2000 to 4000 feet. One little 
plant not yet mentioned is Sibthorpia europcea. It abounds in shady- 
spots. 

One of the most interesting of the plants in the upper woods is 
Daphne laureola, which is usually restricted to levels between 3500 
and 4500 feet. In the woods and thickets it displays a loose strag- 
gling habit ; but when, as on the northern side of the mount ain y , 
it grows exposed on the moors near their upper limits, it presents 
itself as rounded dense bushes three or four feet in height. Yet iir 
is a plant that even here seeks protection, and it selects the dips 
and hollows of the moors and gives a singular appearance to the 
landscape. 

Numerous small craters and gulches in the zone of the upper 
woods afford refuge to plants that under ordinary circumstances 
are confined to the lower woods. The vegetation of the small craters 
on the slopes of this mountain is often especially luxuriant. When, 
as sometimes happens, the crater or gulch is inaccessible, the plants 
attain unusual heights, protected against injury from men and 
animals. Here in a limited space, at altitudes of about 3500 feet, 
one may observe nearly all the trees and shrubs of the slopes of Pico 
from the coast up to 5000 feet, not only those of the upper woods, 
but such as Myrica faya, Rhamnus latifolius, and Viburnum tinus, 
that are ordinarily restricted to the lower woods. In these refuges 
the Tree-Euphorbias are especially at home, and there flourish 
here many herbaceous plants of both wood zones, such as Euphrasia 
grandiflora, a tall Verbascum, Sanicula azorica, and species of 
Habenaria. 

The dominant trees of the lower woods, that is, below 2000 feet, 
are Myrica faya, Erica azorica, and Laurus canariensis. The 
dominant shrub is Myrsine africana. But Rhamnus latifolius, 
Vaccinium cylindraceum, and Ilex perado are also frequent. The 



376 PLANTS, SEEDS, AND CURRENTS 



Laurestinus (Viburnum tinus) is absent in some places and fairly- 
represented in others. The " Pao branco " (Picconia excelsa) is 
now very rare, its timber being much appreciated by the islanders. 
However, single trees may occasionally be noticed in the woods; 
but as a rule it finds a refuge in some inaccessible gulch or small 
crater. Osmunda regalis may be observed at levels exceeding 1000 
feet in moist surroundings at the margin of the woods. Amongst 
the tree-climbers are a Smilax and Hedera canariensis, the undergrowth 
being generally formed by species of Rubus, Myrsine africana, the 
Ivy just named, and Pteris aquilina. In the open districts Calluna 
vulgaris is abundant. 

But the lower woods are essentially the zone of the Faya tree, 
and here, as in the case of nearly all the most conspicuous features 
in the vertical distribution of plants on this mountain, we have the 
corroborative testimony of the Hochstetters. Just as the Junipers 
are restricted to the upper woods, so Myrica faya is characteristic 
of the woods below, and rarely extends much above 2000 feet, except 
when it finds shelter in some gulch or small crater as before described. 
The trees of the lower woods that reach the coast are mainly the 
Faya and the Tree-Heath (Erica azorica). Two plants range through 
the whole height of the mountain, Calluna vulgaris and the narrow- 
leaved variety of Thymus serpyllum. They grow not only on the 
old lava-flows as they reach the coast, but also on the lava surface 
of the summit, and on various kinds of soil, both rich and poor, in 
the intervening levels. 

The Vegetation of the Upland Moors of the Mountain of 
Pico. — There remains for consideration the vegetation of the upland 
moors, which are generally confined between the levels of 2000 and 
4000 feet. The moors form a belt around the greater part of the 
mountain, but are crossed at intervals by broad strips of woodland. 
Lying as they do within the rainy zone, their conditions are nearly 
as moist as those of the upper woods, and they largely usurp their 
place. They are used as pasture-land for cattle, the lower portions 
being under private ownership, while the upper parts marked off 
by a high wall, usually about 3000 feet above the sea, are known as 
the Baldios or Common-lands. These upland moors, which doubt- 
less have been greatly extended by deforestation since the colonisa- 
tion of the group, are characteristic of all the larger islands. In their 
general features and in the association of their plants they often 
display, as already observed, a striking resemblance to Dartmoor. 

Their surfaces on the slopes of this mountain are often marked by 
linear copses of the Tree-Heath, which present a variety of strange 
patterns, that look from a distance like huge hieroglyphs on a light 
green ground. Two objects have here been served. In availing 
himself of the natural growth of the trees, the land-owner has so 
trimmed and directed the growth of the original copse, that at the 
expense of as little ground as possible he obtains shade for his cattle 
in summer and shelter from the cold winds in winter. In the other 
case, whilst clearing his land he has preserved the heath trees, 
when they are frequent, near his boundary lines, and has allowed 
them to propagate themselves only on the borders of his property, 



THE AZORES 



377 



the result being that his land is partially enclosed in a living 
tree-fence. 

Except on the south side, where the mountain rises steeply from 
the coast to its summit, these upland moors have generally an easy 
slope. The bracken (Pteris aquilina) and the tussock of Polytrichum 
give a character to their rolling grassy surfaces. It is pleasant to 
tread their springy turf after the rough descent of the precipitous 
and scantily vegetated lava slopes above; and, if it is summer, 
the multitude of herbaceous plants in bloom will delight the eye. 
One may on the western side distinguish between the boggy lower 
areas, where Sphagna flourish, and the relatively drier upper levels, 
where Peat-mosses do not live ; but more often this differentiation 
is not to be made, and one may stumble on a bed or a pocket of 
Sphagnum without much warning. 

On the drier ground thrive Erythrcea massoni, Lysimachia nemorum 
(var. azorica), Luzula purpureo-splendens, Menziesia polifolia, Poly gala 
vulgaris, Potentilla tormentilla, and Thymus serpyllum (var. angusti- 
folius). Calluna vulgaris forms an occasional scrub, whilst Sibthorpia 
europcea conceals with its foliage the shady side of pits and holes, 
though with the species of Lysimachia it is almost as common in 
the wetter areas. Terrestrial orchids (Serapias, Habenaria) are not 
infrequent, and the turf is dotted with single tufts of Lycopodium 
selago, while Blechnum spicant grows in the higher levels. 

The wetter areas, when of any size, are essentially Sphagnum 
moors, and the Polytrichum tussocks are here more numerous and 
larger, and measure one and a half to two feet high and two to three 
feet across, the Peat-mosses being often closely associated with them 
in their growth. Anagallis tenella, Hydrocotyle vulgaris, and Viola 
palustris grow in great abundance, and among the Carices, Carex 
flava is the most common and sometimes almost monopolises the 
ground. It may be doubted whether the Bog Pimpernel (Anagallis 
tenella) exists in greater profusion in any part of its range than on 
the island of Pico. The writer has walked for miles on the mountain 
moors to the east of the peak, treading on its flowers at nearly every 
step. In the tussocks, or rather hummocks, of Polytrichum, almost 
all the flowering plants of the wet moor in turn find a home; but 
Hydrocotyle vulgaris is most frequently to be noticed growing in their 
midst. The tussocks, by becoming confluent, form in places dense 
beds nearly appropriating the ground. This is to be observed at 
altitudes of 5000 feet on the north side of the mountain, where the 
moor vegetation begins to ascend its steep upper-third. 

The Sphagnum growth is in some localities very extensive, as on 
the south-west side of the mountain between the Serra Gorda and San 
Mattheus. For one and a half or two miles from the Serra the soil 
is stoneless and peaty, and Sphagna form dense growths, a foot 
high or more, around the bases of the shrubs of Erica azorica that here 
clothe the surface. The bushes, in fact, seem to grow out of Sphag- 
num tussocks. The signification of this association is not very 
obvious. Tansley in his Types of British Vegetation (1911, p. 235) 
describes similar growths of Sphagna around the bases of bushes and 
on the stools of Phragmites in the fen formation of East Norfolk, 



378 PLANTS, SEEDS, AND CURRENTS 



and he considers that the acids secreted by the Peat-mosses would 
be neutralised by the alkaline ground- waters. In the coastal swamps 
of the Carolina region a large fern, Woodwardia virginica, grows out 
of low Sphagnum tussocks which are surrounded by standing water 
(Harshberger's Phyt. Surv. N. Amer., p. 441). The Pico locality, 
it should be noted, lies in the midst of a district of basic lavas, rather 
over 2000 feet above the sea. In midsummer its surface is but 
slightly moist, and large masses of dead Peat-mosses are seen. In 
winter the ground would doubtless be very wet. 

Here and there water collects in depressions of the boggy ground 
on these upland moors. Around the edges of the pools grow Littorella 
lacustris, Peplis portula, Car ex stellulata, and Scirpus multicaulis, 
the last in proliferous condition. In the water thrive Callitriche 
aquatica, Potamogeton polygonifolius, and Scirpus f.uitans. Watson, 
in his paper in the London Journal of Botany for 1843, gives a list 
of the plants growing in and around some of these pools on the upland 
moors which he passed on his way to the summit. They include 
Callitriche verna, Carex stellulata, Peplis portula, Potamogeton natans 
(subsequently referred to P. polygonifolius), Scirpus fluitans, and 
Sc. savii. Further remarks on the aquatic and sub-aquatic plants 
of the island of Pico will be found in the following chapter. 

The Secondary Cones on the Slopes of the great Mountain 
of Pico. — Reference has more than once been made to the craters 
of these numerous small cones as sanctuaries for plant life. They 
vary usually from 50 to 250 feet in height, and as far as could be 
gathered show no signs of volcanic heat, their interior as well as 
their exterior slopes being either grassy or w T ooded. Many of them 
are situated in the upland moors or in the zone of the upper woods, 
that is to say, at elevations of from 2000 to 5000 feet above the sea. 
In some instances the craters are inaccessible, and in one case, where 
a narrow gap led into the crater, the interior was once used as a 
corral for cattle. I ascended many of them, and the vegetation of 
their outer slopes depends on whether they rise up in the moors 
or in the woods. Their craters are usually dry, and only in the case 
of the smallest cones do they hold shallow ponds, the abode of aquatic 
plants. In one such crater pool Potamogeton polygonifolius grew 
in the water and Scirpus multicaulis at its sides, there being a growth 
of Sphagnum at its border. (In the case of the numerous crater 
lakelets, that occur off the great mountain in the eastern part of 
the island, a few remarks will be made later on in this chapter.) 
Some of the cones are very regular in form, and one may mention 
in this connection the Cabeza Norte, which lies at the foot of the 
cone proper on its W.N.W. side about 4000 feet above the sea. 
It has a height of 200 feet, and its crater, which is remarkably 
symmetrical in shape, is 500 feet across and is as deep as the hill is 
high. Its interior is partly clothed with shrubs, mostly Erica 
azorica, with a little Ilex per ado. 

The Lake District of the Island of Pico. — This region is 
separated from the eastern slopes of the great mountain by a broad 
saddle, or elevated plain, which is raised not less than 2000 feet 
above the sea. The plain is dotted with small volcanic cones, and 



THE AZORES 



S79 



is in part grassy and in part boggy, cattle grazing here in numbers. 
To the east of it lies the mountainous eastern part of the island, 
with which I became acquainted as far as Santo Amaro on the north 
coast and Ribeiras on the south coast. The general level of this 
upland region is 2500 to 2800 feet, and from it rise abruptly several 
isolated peaks, the highest having an altitude of about 3500 feet. 
Numerous large mountain lakes lie interspersed among the peaks 
at elevations of 2500 to 2900 feet. They are evidently shallow, and 
are usually 300 to 500 yards in length. With the exception of the 
" Lagoa Rosada," not one of them could be regarded as occupying 
old crater cavities. They are : — 

1. The " Lagoa das Teixas." behind San Roque. 

2. The " Lagoa Paul," at the foot of Pico Topo. 

3. The " Lagoa Caiado," lying W.S.W. of Praynha do Norte. 

4. The " Lagoa Rosada," in the Caldeira de Santa Barbara dis- 

trict. 

5. The " Lagoa do Ilheo," behind Santo Amaro. 

6. The " Lacroa Negra," behind Santo Amaro. 

The peaks are mostly bare of trees and shrubs, and on their steep 
slopes sheep browse in numbers. The only one of them that I 
ascended was Pico Topo, which lies behind Lagens, and proved to 
have an altitude of only about 3300 feet instead of 5357 feet as stated 
in the Admiralty chart. It is a long, ridge-shaped, hog-backed 
mountain, which rises precipitously from the coast on the southern 
and eastern sides, but is elevated only about 700 feet above the plains 
on its north side. 

Very moist conditions prevail in the elevated plains between the 
mountains amongst which the lakes lie. In this upland region, 
2500 to 2800 feet above the sea, there are extensive wet moors, where 
Sphagnum, Polytrichum, Carices, Anagallis tenella, Hydrocotyle 
vulgaris, etc., thrive, as well as large areas covered with wood and 
bush, where the Juniper is at home, and where filmy ferns (Hymeno- 
phyllum and Trichomanes) abound. The humidity of this region 
affords a great contrast to the relatively dry conditions prevailing 
at similar altitudes on the slopes of the great cone of Pico. Even 
in fine August weather the grass and herbage in the trails remained 
wet during most of the day, and one's boots and leggings quickly 
became soaked through even late in the morning. It is the land of 
the Juniper and of the plants of the boggy moor ; and though drier 
bracken moors are frequent, where, besides Pteris aquilina, there 
grow C allium vulgaris, Erythrcea massoni, the Azorean variety of 
Lysimachia nemorum, Lycopodiam selago, Polygala vulgaris, Potentilla 
tormentilla, etc., it is to the two first-named features that the lake region 
between the mountains owes its most conspicuous characters. 

In the woods the Junipers attain a much larger size than on the 
slopes of the great mountain of Pico, their height being often fifteen 
or sixteen feet, and their diameter fifteen to eighteen or even twenty 
inches. Here the Loranth, Arceuthobium ozycedri, flourishes in 
places on the Junipers. The other components of the bush are the 
Tree-Heath {Erica azorica), the Tree-Euphorbia (E. stygiana), 



380 PLANTS, SEEDS, AND CURRENTS 



Laurus canariensis, Myrsine africana, the common species of Smilax, 
Vaccinium cylindraceum, etc., and among the ferns, Acrostichum 
squamosum, Dicksonia culcita, and Osmunda regalis, and we may 
here add Lycopodium complanatum. The Vacciniums come next 
to the Junipers in frequency, and grow so rankly that they may 
reach a height of from twelve to fifteen feet, thus becoming arbores- 
cent. At one time Taxus baccata flourished in this region, and its 
name is still preserved in the name of the lake behind San Roque, 
" Lagoa das Teixas " ; but it is rare in that locality now, and seems 
mainly to survive in the gulleys, about 2000 feet above the sea, on 
the mountain slopes behind that village. I come now to the descrip- 
tion of the lakes. 

The Lagoa das Teixas (Lake of the Yews), located as just stated, 
is a shallow lake, 350 to 400 yards in length, and half that in breadth. 
It is elevated about 2500 feet above the sea. It is also known as 
the Lagoa do Capitao Alexandre, after a former governor of the island 
and owner of the property. The shallows are largely occupied by 
Potamogeton polygonifolius, which covers no small part of its surface. 
A broad margin of Scirpus fluitans, so dense in growth that one can 
walk upon it, skirts the water's edge. Outside this is a boggy belt 
where thrive Sphagnum, Scirpus multicaulis, Carex flava, Hydrocotyle 
vulgaris, Anagallis tenella, etc. Flourishing in places on the south 
and west sides, and mainly covering the soppy marginal flats, is 
the large form of Littorella lacustris, with long cylindrical leaves 
measuring six to nine inches. 

The Lagoa do Caiado lies, as the crow flies, about three miles 
W.S.W. from Praynha do Norte, in the district known as the Serra 
da Praynha. Elevated about 2600 feet above the sea, it is about 
500 yards long and 400 yards broad. Like the Lagoa das Teixas, 
it occupies a shallow basin between the hills and cannot be very 
deep. At its north-east end the banks holding back the waters 
are so low that apparently it would not be very difficult to make 
a cutting and drain its waters down the mountain sides. Sphagnum 
thrives in the boggy margins, and here grow Carices, such as Carex 
flava, Scirpus multicaulis, Anagallis tenella, Hydrocotyle vulgaris, 
etc., whilst Peplis portula is common at its muddy edges. Littorella 
lacustris and Isoetes azorica flourish at the borders, both displaying 
two forms, the dwarfed form of the mud-flat and the large, long- 
leaved form of the watery mud or of the deeper water. Some of 
the deep-water plants of Isoetes, that were washed up on the banks, 
had leaves eighteen to twenty inches in length. (Further details 
relating to the mode of occurrence of these two interesting plants 
are given a few pages later.) Potamogeton polygonifolius covers 
extensive areas of the shallows of this lake. In one or two places, 
where the bush growth of the surrounding district descends to its 
borders, Osmunda regalis may be observed close to the water's 
edge. 

The Lagoa Paul, lying just under Pico Topo on its north-west 
side, was dry when I visited it on July 30, 1914. When full of water 
it would be smaller than the Caiado Lake. On the surface of the 
exposed mud-flats, which were still moist, grew in quantity the 



THE AZORES 



381 



dwarfed forms of the species of Isoetes and Littorella above named ; 
the latter formed almost a turf. 

The Lagoa Rosada, or the Rosy Lake, is situated in the middle of 
the island between Ribeiras and Praynha do Norte and near the 
Caldeira de Santa Barbara, indicated in the chart. Elevated about 
2950 feet above the sea, it occupies the bottom of a broad basin, 
which may possibly be of crateral origin, and it is the only one of 
the large mountain lakes that could be so regarded. It is oval in 
shape, and is between 200 and 250 yards long, and from 100 to 150 
yards broad. Viewed from the slopes above in the late afternoon, 
its waters had a beautiful inky-blue hue, so that " Lagoa Ccerulea " 
seemed a more appropriate name. Besides Potamogeton polygoni- 
folias, the two forms of Isoetes azorica and Littorella lacustris here 
thrived. 

Lying close together in a level district on the top of the mountains 
behind Santo Amaro, and elevated between 2800 and 2900 feet above 
the sea, are the Lagoa do Ilheo (Lake of the Isles) and the Lagoa 
Negra, or the Black Lake. The Lake of the Isles is about the size 
of the Caiado Lake, if not larger. It contains two islands, and is 
half-covered by the Potamogeton so common in these mountain 
lakes; whilst a tall form of Scirpus palustris, two feet in height, is 
not uncommon in the shallows. The Lagoa Negra is about 300 
yards in length and oval in shape. Here were to be seen the species 
of Potamogeton, Littorella, and Isoetes above named. 

A number of small, circular, shallow lakelets, twenty-five to fifty 
yards across, fill the bottom of the craters of the numerous small cones 
dotted about this elevated lake region. Occasionally in midsummer 
they are almost dried up, when the still moist muddy surface may be 
covered by a turf of Scirpas fluitans, which doubtless resumes its 
usual aquatic habit when the lakelet refills in the rainy season. 
More often they are appropriated by the ubiquitous Potamogeton 
polygonifolius, or, when the surface is clear, plants of Isoetes azorica 
and Littorella lacustris in their two forms thrive in their waters and 
at their borders. It may be here added that almost all the aquatic 
and sub-aquatic plants previously mentioned in connection with 
the island of Pico flourish in one or other of the numerous small 
crater lakes of the island, Sphagnum often growing at their borders. 

In the vegetation around the large lakes of this region one can 
sometimes recognise a succession of formations. Whilst the Potamo- 
geton before named occupies the shallows, Scirpus -fluitans monopo- 
lises the soppy ground at the lake's border, and outside this is a 
broad belt of Sphagnum, where Scirpus multicaulis, Car ex flava, 
Anagallis tenella, and Hydrocotyle vulgaris thrive. 

With regard to the occurrence of Littorella lacustris and Isoetes 
azorica in this region of the mountain lakes, some further remarks 
may here be made. Both display two forms, a dwarfed form on 
the exposed mud-flats, and a large form with long cylindrical leaves 
growing in the deeper water, as in the case of Isoetes, or where the 
water just covers the ooze at the lake's margin, as with Littorella. 
Whilst the dwarfed plants of Littorella lacustris were well in flower 
at the end of July, the large plants were only showing the flower- 



382 PLANTS, SEEDS, AND CURRENTS 



buds ; the latter possess cylindrical leaves, six to nine inches long, which 
lie prostrate in the water, and are not erect, as has been sometimes 
described. It was evident that the floating growths of Potamogeton 
polygonifolius were inimical to the growth of the large forms of 
Littorella and Isoetes. They are rapidly extending in the ponds, and 
not improbably will ultimately exterminate the last-named plant. 

The Uplands of the Island of San Miguel. — The great upward 
extension of the cultivated zone, and the large intermingling of 
foreign trees and shrubs with the indigenous trees and shrubs of 
the lower slopes up to 2000 feet, will cause our interest to be mainly 
centred on the upland regions as best illustrated in the mountainous 
eastern portion of this island. It may, however, be observed that 
on the lower slopes of San Miguel, as far as they are still held by the 
indigenous flora, occur the characteristic trees and shrubs of the 
lower woods of Pico, such as Erica azorica, Laurus canariensis, 
Myrica fay a, Myrsine africana, Viburnum tinus, etc., the last named 
being more generally distributed over the island than it is on Pico. 

Without further remark I will proceed with my notes on the 
ascents of the Pico da Vara Range in the eastern part of San Miguel, 
a range that culminates at an altitude of 3570 feet in the peak of 
that name, the highest point of the island. My ascents were made 
in the latter part of February ; but it is evident from Drouet's account 
of the vegetation of the higher slopes of the range in May, that 
except for the plants in bloom my notes will give a fair idea of the 
general characters of the larger vegetation in that weather-beaten 
region. 

Pico da Vara, the highest peak of the range, rises abruptly about 
600 feet at the eastern extremity of a long, flat-topped, wind-swept 
ridge that forms the mountainous backbone of the eastern part of 
San Miguel, and attains a general level of about 3000 feet above 
the sea. It is a cloud-begirt, wind-buffeted region of heavy rainfall, 
and it receives the full force of the Atlantic gales. One may walk 
for three miles along the flat crest of this ridge from its western 
end without changing one's level more than 200 feet. The soil 
there is derived from the prevailing coarse, andesitic, pumiceous 
tuffs; but the materials are only partially disintegrated, so that 
one crunches underfoot the loose, sodden, pumice gravel that strews 
the surface. On the crest of this mountainous backbone occur 
stunted growths of Juniperus oxycedrus and Laurus canariensis 
(Laurel), mingled with Myrsine africana, Vaccinium cylindraceum, 
and the Culcita fern (Dicksonia culcita) ; and in response to the 
prevailing moist conditions there are tussocky growths of Polytrichum. 
At the western end of the range, where the ridge broadens out into 
a kind of table-land, the surface is in places boggy, and in the pools 
grow Potamogeton polygonifolius and Callitriche aquatica, with 
Sphagnum and Juncus at the borders. 

But the stunted growths of the Juniper and the Laurel largely 
monopolise the higher slopes of this mountain ridge, the Laurel 
reaching to the top of the ridge and the Juniper extending to the 
summit of the eastern peak. In this wind-swept region their height 
is usually between two and three feet; but where the exposure is 



THE AZORES 



383 



greatest the Juniper grows semi-prostrate on the ground. Besides 
the Juniper, Dicksonia culcita also reaches the very top of the island, 
being accompanied by dwarfed growths of Myrsine africana and 
Vaccinium cylindraceum. 

Yet this is but a winter view of the vegetation of the higher levels 
of the Pico da Vara Range. In summer, when picnicking parties 
from the Furnas Valley ascend these mountains, herbaceous plants 
in abundant bloom adorn the slopes; and, if the weather is fine, 
there would be little in these breezy heights, with a magnificent 
panorama at one's feet and a clear sky overhead, to suggest that 
any risks would attend an ascent in winter. But the little stone 
crosses on the top of the ridge tell another story. Shepherds, over- 
taken by the blizzard in mid- winter, have lain down and died ; and 
under conditions that were certainly elemental the writer had an 
experience on these storm-swept levels of the influences that have 
oppressed the Junipers and Laurels through the ages. He was 
overtaken by a succession of squalls from the north-west. For 
nearly an hour, enveloped in the clouds and without any shelter, 
he was exposed to a pitiless storm of wind and rain. Subsequently, 
on reaching the summit of the peak, he found Sibthorpia europcea in 
foliage in the shelter of a small pit, the sides of which were lined by 
Liverworts (Hepaticce) ; but with the exception of the narrow-leaved 
variety of Thymus serpyllum, in leaf only, there was little else in 
the lesser vegetation of these heights to remind one of the summer 
dress of the slopes of Pico da Vara. 

Judging from Drouet's reference to his ascent of this range, the 
general extent of the larger vegetation at the top was much the same 
in 1857 as it was in 1913. But the tale of the pumice-strewn soil 
of the upper slopes is fairly clear. The interval that has elapsed 
since the great eruption of the Furnas Valley in 1630, when, according 
to Walker, all the vegetation in the eastern part of the island was 
overwhelmed by ashes and covered to a depth of many feet, has not 
been long enough for the restoration of the original forests on these 
mountain slopes. The struggle of the plants to regain their own 
has been rendered still more difficult by the repressive influence of 
the winds on these stormy heights. 

Ascent of Santa Barbara, the highest Mountain of Terceira, 
3500 Feet above the Sea. — My ascent was made from Angra in 
the middle of April. Although the zone of cultivation extends up 
to about a thousand feet, that does not represent the limits of man's 
destruction of the original forests, since on the higher slopes, where 
doubtless these forests once grew, scrub is now only to be found. 
The scrub is formed chiefly of Juniper and Calluna vulgaris (Ling), 
with Myrsine africana in places. The Ling occupies the lower 
slopes below 2200 feet where the ground is dry and the soil poor and 
stony, and it is accompanied by Thymus serpyllum in its dense- 
growing, trailing, narrow-leaved Azorean form. The Juniper 
predominates on the higher slopes, where the ground is wet and often 
boggy, and where Sphagnum and Polytrichum thrive. The higher 
parts of this mountain are much wind-swept and often cloud-invested, 
and on account of the clouds, rain, and wind I was unable to make 



384 PLANTS, SEEDS, AND CURRENTS 



a long stay on the summit. But the ascent is by no means an inter- 
esting experience for the botanist, since his thoughts are more likely 
to dwell on the lost forests than on the surviving vegetation. 

The Characteristic Coast Plants of the Azores. — Though 
my experience was mainly confined to the island of Pico, it can be 
supplemented by notes made on Fayal and San Miguel. The coasts 
of the islands of the Azores are mostly rock-bound and often pre- 
cipitous, beaches of any size being, as a rule, infrequent. The most 
typical plants include the following, which are more or less generally 
distributed over the group — Beta maritima ; Crithmum maritimum ; 
Euphorbia azorica, regarded by some as a variety of the South Euro- 
pean E. pinea, L. ; Euphorbia peplis ; Hyoscyamus albus ; Juncus 
acutus ; Plantago coronopus ; Polygonum maritimum ; Salsola kali ; 
Silene maritima ; Spergularia marina, probably far more widely 
distributed in the group than is admitted by later authors; and 
Statice limonium. 

One of the most interesting localities for beach plants that I came 
upon was the sandy beach of Porto Pym, in Fayal. In their order 
of frequency the plants were Ipomoea carnosa, R. Br., Salsola kali, 
Euphorbia peplis, Cakile edentula, and Polygonum maritimum. Some 
of them, such as the species of Ipomoea and Cakile, are known to have 
been growing on this beach for more than seventy years, having 
been found there by Watson in 1842, and collected since by other 
botanists, as by C S. Brown in 1894. It is probable that Cakile 
edentula was originally introduced with ballast, a matter discussed 
in the general treatment of that plant. 

The most frequent plant on the rocky coasts of Pico is Euphorbia 
azorica ; but Plantago coronopus and Juncus acutus are also common. 
On the sandy beaches grow in places Polygonum maritimum, often 
in association with Hyoscyamus albus ; whilst Salsola kali occurs 
scantily. Silene maritima and Spergularia marina grow both on 
the sand and on the rocks, and sometimes in sandy pockets in the 
lava rock. Crithmum maritimum (Samphire) is found here and there 
on the rocks, as at Praynha do Norte; but it is much appreciated 
by the inhabitants for eating with fish, and it is likely that its relative 
scarcity on the Pico coasts is due to this cause. On the beach just 
south of Magdalena I found Ipomoea carnosa, previously only known 
in this group from the island of Fayal. 

On the rocky coast at San Mattheus and at Magdalena there 
exists a peculiar plant, concerning the identity of which I am in 
doubt. It is a very fleshy plant, of which unnamed specimens 
from San Jorge in the herbarium of the Ponta Delgada Museum 
are enclosed in a Mesembryanthemum cover, having been collected in 
1905 and 1908, or ten or twelve years after Trelease's visit. The 
plants grow prostrate on the lava rocks, and have purplish terminal 
flowers. They exist in quantity on the rocky flat close to a windmill 
just north of the town of Magdalena. The species comes nearest 
to Mesembryanthemum ; but it has a four-valved capsule that dehisces 
loculicidally, leaving the axis in the centre of the fruit. The seeds 
have the appearance of Stellaria seeds, and are round, blackish, 
scrobiculate or warty, about a millimetre across, and have an embryo 



THE AZORES 



385 



curved around a mealy albumen. In another cover in the herbarium 
were specimens of quite another plant, labelled Tetragonia expansa, 
from the Azores, the island not being named. I find no reference 
to any of these plants in the pages of either Watson or Trelease. 

Another Azorean shore plant is Solidago sempervirens, an American 
littoral species, which, as we learn from Seubert, extends inland to 
a height of 1000 feet above the sea. Campanula vidalii, which is 
peculiar to the Azores and occurs principally on the sea-cliffs and 
coast rocks of Flores, is specially discussed in the notes on Azoreart 
plants at the end of Chapter XIX. 

Summary 

1. During his two sojourns in this group the writer was principally 
engaged in investigating the altitudinal ranges of the indigenous 
plants; and with this object the vegetation of the great cone of 
Pico, by far the loftiest mountain in the archipelago, was especially 
studied. His ascents, and the best methods to be followed in examin- 
ing the higher slopes of the mountain, are first described (pp. 359-61). 

2. A sketch of the history of the botanical investigation of the 
Azores is next given. This exploration, which commenced with a 
small collection of dried plants made on Fayal in 1775 by George 
Forster, one of Cook's naturalists, and with collections of living 
plants made for Kew Gardens by Masson a year or two later, has 
since been carried out by a number of botanists and naturalists of 
various nationalities — American, English, French, German, Portuguese, 
and Swiss. We may mention here Guthnick and the Hochstetters 
in 1838; Watson in 1842; Carew Hunt during 1844-8; Drouet 
(zoologist), Morelet (zoologist), and Hartung (geologist), all in 1857 
Godman (zoologist) in 1865; Brown in 1894; Trelease in 1894 and: 
1896 ; and last, but by no means least, resident Portuguese botanists,, 
such as Carreiro, Machado, and Sampaio. The works that form 
landmarks in the investigation of the flora are those of Seubert 
(1844), Drouet (1866), Watson (1870), and Trelease (1897) (pp. 361-4). 

3. Before dealing specially with the vegetation of Pico, allusion 
is made to the heights of the islands of the Azores (p. 364). This leads 
one to compare the conditions for forest growth in this group with 
those in the Canaries and in Madeira, a comparison that supplies 
an opportunity of forecasting the correlation of the three floras, 
and leads us to look for in the Azores only the evergreen shrubs and 
trees of the Canarian Laurel woods (p. 365). 

4. The general profile of the great mountain of Pico is then described 
(p. 366); and in this connection the bluffs of the Ribiera Grande 
are mentioned as presenting one of its principal spectacular features 
(p. 366). 

5. After disposing of the not uncommon error that the higher 
slopes of the cone are barren, the author deals with the extent of 
the vegetation on the mountain. The lower slopes are generally 
well vegetated up to 4500 or 5000 feet, moor and grass land pre- 
dominating in their higher levels between 2000 and 4000 feet. But 
woods are well developed in places, the lower woods on the western 

c c 



386 PLANTS, SEEDS, AND CURRENTS 



side and the upper woods on the south-eastern side. They are 
essentially formed of evergreen shrubs and trees; but on account 
of the persistent agency of the woodcutter through centuries the 
trees, except when specially preserved, rarely exceed twenty feet 
in height, and are usually not more than fifteen or sixteen feet. 
Dwarfing begins, as a rule, at about 4000 feet, as the effect of deficient 
-soil and of exposure to strong winds. Above 5000 feet are the 
sparsely- vegetated, precipitous lava slopes of the cone proper; 
tbut in spite of the conditions five or six kinds of plants, usually as 
stunted and creeping growths, reach the summit (p. 367). 

6. The writer then comes to his special study, the zones of vegeta- 
tion on the great mountain of Pico. This subject is not dealt with in 
the later works on the flora, which are almost exclusively devoted 
to the systematic treatment of the plants, and were the only sources 
of information accessible to him at the time of his visits. The 
result was that after he had completed his study he found that in 
the main he had long before been anticipated by the earlier German 
and French investigators, particularly by the Hochstetters (p. 368). 
The zones of vegetation adopted by the writer for this mountain do 
not differ very materially from those of his predecessors. They are 
as follows : — 

I. The Lower Woods, or the Faya zone, Myrica faya being one 
of the most characteristic of the trees. The zone extends usually 
from the coast up to 2000 feet. Besides the Faya, the other trees 
peculiar to the zone are Bhamnus latifolius, Persea (Laurus) indica, 
and Picconia excelsa. Among the trees that are abundant in both 
the Upper Woods and the Lower Woods are Ilex perado, Erica azorica, 
and Laurus canariensis. Of the shrubs the Laurestinus (Viburnum 
tinus) is restricted to the zone ; whilst Vaccinium cylindraceum and 
Myrsine africana, abundant here, are equally common in the Upper 
Woods. 

II. The Upper Woods, or the Juniper zone. Juniperus oxycedrus 
(var. brevifolia), Daphne laureola, and Euphorbia stygiana are the 
most distinctive of the trees and shrubs ; whilst Erica azorica, Ilex 
perado, Laurus canariensis, Myrsine africana, and Vaccinium 
cylindraceum are as characteristic of this as they are of the zone 
below. Taxus baccata, now almost extinct, thrived originally in 
the lower levels of the Upper Woods and in the higher levels of the 
Lower Woods. The Loranth, Arceuthobium oxycedri, is a frequent 
parasite on the Juniper trees. This zone extends usually from 2000 
.to 4500 feet, but is continued as a scrub up to 5500 feet. 

III. The highest zone of the cone proper, 5500 to 7600 feet. All 
^£'he plants growing on these scantily vegetated, steep, lava slopes 
tiave climbed up from the lower levels, principally from the moors, 
as described below. They include Calluna vulgaris, Menziesia 
polifolia, Thymus serpyllum (var. angustifolius), Polygala vulgaris, 
and Agrostis castellana, all of which reach the summit. 

IV. The zone of the Upland Moors, 2000 to 4000 feet, which has 
been formed at the expense of the Upper Woods around much of 
the mountains. Here we find many of the features of a Devonshire 
moor, as on Dartmoor. The most striking general features are the 



THE AZORES 



387 



Bracken (Fteris aquilina), the large tussocks of Polytrichum, and the 
beds of Sphagnum. Among the most frequent flowering plants 
are Anagallis tenella, Calluna vulgaris, Carex flava, Erythrcea massoni, 
Hydrocotyle vulgaris, Luzula purpureo-splendens, Lysimachia nemorum 
(var. azorica), Menziesia polifolia, Poly gala vulgaris, Potentilla 
tormentilla, Sibthorpia europ&a, Thymus serpyllum (var. angustifolius), 
and Viola palustris. In and around the pools grow Callitriche 
aquatica, Carex stellulata, Littorella lacustris, Peplis portula, Pota- 
mogeton polygonifolius, Scirpus fluitans, S. multicaulis, etc. (pp. 368-71). 

7. After discussing the prevailing climatic conditions on the upper 
slopes of the great mountain (p. 371), the writer gives a general 
account of its vegetation, commencing at the summit; but only 
some of the special features can be here alluded to. Thus it is noted 
(p. 373) that occasional stragglers from the upper woods reach far 
up the mountain, stunted specimens of Ilex perado having been 
observed at 6300 feet. Then it is remarked that on the scantily- 
vegetated lava slopes, between 5000 and 6000 feet, a number of 
herbaceous plants find a sanctuary in the beds of Ling (Calluna vulga- 
ris), and that even the Juniper, as dwarfed specimens only six inches 
high, finds protection there (p. 373). The prevalence of filmy ferns? 
such as Hymenophyllum tunbridgense, on the tree-trunks of the uppei 
woods indicates the humidity of the conditions in that zone, the 
limits of which roughly correspond to those of the rainy belt (p. 375). 
Two plants range through the whole height of the mountain, namely, 
Calluna vulgaris and the narrow-leaved variety of Thymus serpyllum 
(p. 376). Special reference is made to the unusual development 
of Sphagnum on the south-west side (p. 377). 

8. The manner in which small craters and gulleys on the higher 
slopes serve as refuges for plants of the lower slopes is then treated. 
In this way plants of the lower woods find a home in the upper 
woods, and plants of the upper woods in the slopes above (pp. 374-5). 

9. The mountain -lake district of the island of Pico is next de- 
scribed. Here several lakes occur at altitudes of 2500 to 3000 feet 
in the midst of a region of extensive wet moors and of large areas 
covered with wood and bush. Very moist conditions prevail in 
the woods, and here the Junipers attain their largest size, the compo- 
nent trees being those of the upper woods of the great cone. Yews 
(Taxus baccata) were once frequent in this locality, but are now 
rare. The lakes are described in detail ; and in the account of the 
vegetation growing in and around them the frequent association of 
Littorella lacustris with a species of Isoetes is noticed (pp. 379-82). 

10. Some remarks are then made on the vegetation of the island 
of San Miguel. On the lower slopes, so far as they are still held by 
the indigenous flora, occur the characteristic trees and shrubs of 
the lower woods of the mountain of Pico. The writer describes 
his ascent in winter of Pico da Vara, the summit of the island, and 
he observes that stunted growths of Juniper and Laurel (Laurus 
canariensis) largely monopolise the higher levels of this mountain 
ridge (pp. 382-3). A short account is given of his ascent of Santa 
Barbara, the highest summit of Terceira, an ascent that is deprived 
of much of its interest through the destruction of the forests (p. 383). 



388 PLANTS, SEEDS, AND CURRENTS 



11. Then follows a short discussion of the seashore plants of the 
Azores, of which the most characteristic seem to be — Crithmum 
maritimum, Euphorbia azorica (perhaps a form of E. pinea of South 
Europe), Euphorbia peplis, Hyoscyamus albus, J uncus acutus, 
Polygonum maritimum, Salsola kali, Silene maritima, and Spergularia 
marina (p. 38 4 )?■ 

12. Under the head of " The Wells of Pico," in Note 36 of the 
Appendix, the extensive soakage seaward of underground waters is 
noticed; and evidence is adduced to show that this is a common 
phenomenon in large islands, and that sometimes fresh- water thus 
derived issues as submarine springs off the coast. On the great 
cone of Pico there are no permanent streams and no springs, the 
poorer inhabitants of the coast towns and villages mainly depending 
on the slightly brackish water of wells sunk in the rubble behind 
the beaches. Off the cone, in the eastern part of the island, perennial 
springs occasionally exist high up the slopes of the mountains. 

1 Frankenia pulverulenta is also an Azorean shore plant which, however, 
rarely came under my notice. 



CHAPTER XVIII 



the Azores (continued) 

The Proportion of Native or Indigenous Plants in the 
Azores. — In these pages we are concerned only with the native 
flora, and it may at once be remarked that it was in all probability 
extremely limited. The matter of the introduced plants cannot 
therefore be dealt with here in any detail; but, from what follows, 
it will be evident that in restricting the field of discussion to the 
native plants, we assume a very great reduction in the size of the 
present flora, a flora which has often been erroneously described 
in general references to the archipelago as in the mass indigenous. 
The very opposite is, indeed, the case; and if we wish to obtain 
a sense of proportion in this respect we cannot do better than go 
back to the writings of the earlier botanists interested in the flora, 
those who, like Seubert and Hochstetter, employed only the truly 
indigenous plants to characterise their zones of vegetation above 
the region of cultivation. 

The islands have been colonised for more than four centuries, 
and during that period multitudes of species have been introduced, 
either by accident or by intention. Without discrimination, it 
would be possible to make an extensive collection at the present 
time that would include hardly any of the native flowering plants, 
and the same could have been done a century or two ago. In fact, 
a small collection of about twenty-seven species, gathered by George 
Forster on Fayal in 1775, was almost entirely composed of plants 
that had been introduced since the discovery of the islands (see 
Note 33 of the Appendix). Trelease, the most authoritative of 
recent investigators of the flora from the standpoint of the systematist, 
finds no difficulty in seeing how " most of the existing species may 
have been introduced by ordinary means, largely through human 
agency, since the discovery of the islands " (p. 67); and one cannot 
be many weeks in the group without recognising the correctness of 
this opinion. Watson's total of 439 flowering plants is increased 
in Trelease's pages to about 560; but I should imagine that the 
original flora did not comprise 200 species, and that the plants which 
gave their impress to the vegetation did not amount to a hundred. 

Watson makes but little effort, as he himself admits, to distinguish 
the introduced plants in his catalogue. His position with regard 
to alien plants is not easy to appreciate now. The old Forbesian 
hypothesis of a great continental extension of Europe westward 
would, if applied to the Azores, scarcely raise the question of intro- 
duced plants. Watson was aware of this, and although taking a 

389 



390 PLANTS, SEEDS AND CURRENTS 



neutral attitude in the matter he adopted the implication as regards 
alien plants. He considered that all " recorded constituents " of 
the Azorean flora should be taken into our " statistical reckonings " 
(p. 264), and he made a numerical analysis (p. 272) without any- 
further differentiation than one based on geographical considerations. 
The results were used by Godman, with no comment on the pre- 
dominant proportion of alien plants, in his concluding general remarks 
on the natural history of the islands (pp. 332, 334), and, as is noted 
below, by other writers on insular floras. 

The effect has been unfortunate, since these writers have treated 
Watson's catalogue of 439 plants as a list of native plants. He him- 
self remarks (p. 262) that his catalogue includes many species that 
have been introduced into the Azores ; but evidently it did not fall 
within the scope of his work, as he viewed it, to discriminate to any 
extent between the natives and the aliens among the plants. To 
take one instance, Watson's list includes about two dozen species 
in all of Medicago, Trifolium, and Lotus, of which the majority must 
have been introduced since the discovery of the islands; yet there 
is nothing to indicate it. Then again, of the fifty-one grasses named 
he only particularises three as possibly introduced. So also of the 
six species of Geranium and Erodium, almost all of them common 
ruderal species, of the sixteen species of Labiatce, which include many 
roadside and waste plants spread by cultivation, and of such familiar 
world-ranging weeds as Oxalis corniculata, Plantago major, P. lanceo- 
lata, Rumex crispus, etc., nothing is said of their alien origin. 

The outcome of this will now be shown. When Godman in his 
book on the group (p. 342) compared the proportion of peculiar 
Azorean plants with those for birds, insects, and land-molluscs, 
he was employing Watson's entire list of plants as though all were 
natives of the islands. Then again there was little in Watson's 
work to guide Wallace in discriminating between native and foreign 
flowering plants, when he made an analysis in his Island Life of the 
439 Azorean species based on their capacity for dispersal. Yet 
he was fully sensible of the difficulty involved. " There can be " 
(he writes, edit. 1892, p. 260) " little doubt that the truly indigenous 
flora of the islands is far more scanty than the number of plants 
recorded would imply, because a large but unknown proportion of 
the species are certainly importations, voluntarily or involuntarily, 
by man. ... It is almost impossible now to separate them, and Mr. 
Watson has not attempted to do so." He goes on to say that even 
if only half of the species are truly indigenous there would remain 
a wonderfully rich and varied flora to have been carried by the 
various means of dispersal. But apart from this, the danger of 
treating all the plants in Watson's list as native plants has not always 
been avoided. Thus, in comparing the endemic element in insular 
floras, Watson's total for the Azores has been sometimes utilised as 
if it were composed entirely of native plants. This is the case in 
a list given in the Introduction to the Botany of the Challenger Expedition 
(p. 33). Then again in works of reference the same thing is done. 
Thus in the article on the Azores in the 9th edition of the Encyclo- 
paedia Britannica, which was written before 1875, all the 478 flowering 
plants, ferns, and lycopods, etc., of Watson's list are characterised 



THE AZORES 



391 



as " generally considered as indigenous." Yet Watson's attitude 
reflected the prevailing opinion among botanists in this matter. 
Hooker, in his famous lecture on Insular Floras in 1866, a lecture 
which has formed the foundation of all later studies of these floras,, 
would almost seem to imply that the 350 species of flowering plants, 
then known were all natives. 

It is not easy for us now to grasp the pre-Darwinian conception 
current in the middle of last century. It was the period of change 
between two eras, and it was left to Trelease in recent years to 
recognise the limited character of the true native flora of this group.. 
The flowering plants designated by him as introduced since the 
occupation of the islands, including weeds, escapes, casuals, etc., 
number in all nearly 200 ; but even Trelease omits to mark as alien 
to the native flora a considerable number of species, such as Lamium 
purpureum, Stachys arvensis, Oxalis corniculata, Geranium molle? 
G. robertianum, G. dissectum, Galium aparine, etc., amounting pro- 
bably to almost another hundred, which must be regarded as having 
been introduced since the discovery of the archipelago. 

One way of testing this matter, as suggested to me by Mr. Hemsley, 
is to take the case of the New Zealand flora, where the introduced 
plants have been carefully discriminated by Cheeseman. This, 
however, would probably develop into a much larger undertaking 
than I could begin now, since numbers of collateral questions would 
arise, and the area of comparison would certainly require to be greatly 
extended as the inquiry proceeded. Unless some abler worker takes 
up the subject, I hope to begin the task some day. It would be 
important to eliminate the agency of man, direct and indirect, 
from every flora, and to apply the same method to all. Such an 
inquiry might be almost as ruthless in its effects on the British flora,, 
as it would undoubtedly be in the case of that of the Azores. As 
applied to the group just named, the term " native flora " denotes 
the plants in the islands before their occupation by man. It has 
in practice a widely different meaning in the case of the British 
Isles, and includes a host of ruderal plants. Yet if a weed had been 
present here for half a million years, it would still be a weed and never 
a part of the native flora. 

Whatever the antiquity of the weed, its differentiation from the 
native plants of a flora, or, in other words, the disentanglement of man's 
influence in the history of the plant- world, becomes the first requisite 
for the proper study of distribution. Whether a region was first 
occupied by man 400 or 400,000 years ago matters little. The weed 
of to-day is the weed of prehistoric ages, and its story is bound up 
with the story of man on this globe. Results, both unexpected and 
important, would be the outcome of such an investigation. 

Probable Composition and General Characters of the 
Original Forests of the Azores. — Although he did not see his 
way to assist us in the differentiation of the weeds, Watson (p. 268) 
gives some valuable suggestions that enable us to form a mental 
picture of most of the general characters of the dense woods that 
covered these islands at the time of their discovery. We may here 
emphasise his opinion that evergreen shrubs and trees, with ferns 
and mosses, formed the principal feature of the vegetation, and that 



392 PLANTS, SEEDS, AND CURRENTS 



" a close forest of evergreens must have formerly covered the ground." 
After a few weeks in the islands the present writer found himself 
unconsciously restoring the evergreen woods that once predominated 
in the group. All the trees and shrubs indicated by Watson as 
composing the original forests are named below, with one exception, 
Myrtus communis, the indigenous character of which has not always 
been admitted. Four others have been added in my account, 
namely, the species of Taxus, Euphorbia, Smilax, and Rhamnus, of 
which the first has been recognised by Trelease and others as originally 
native, whilst the other three are peculiar Macaronesian species 
(Macaronesia comprising the Azores, Madeira, and the Canaries) 
that are held by Watson as well as by Trelease as truly indigenous 
Azorean plants. All were evergreens, even Prunus lusitanica. 

Amongst the trees, Erica azorica, Laurus canariensis, Myrica fay a, 
and Juniperus oxycedrus (var. brevifolia), would have been most 
frequent. Ilex perado would have been well represented, together 
with Picconia excelsa and Taxus baccata. Rhamnus latifolius, & 
sub-evergreen, doubtless took its share, together with Prunus 
lusitanica, the latter being now only known from San Miguel. The 
Tree-Euphorbia (E. stygiana) was probably more frequent than it 
is at present. Among the evergreen shrubs, Myrsine africana, it 
is likely, took a leading part ; Vaccinium cylindraceum was abundant ; 
and whilst Daphne laureola flourished in the upper woods, Hypericum 
foliosum was common in the lower woods. The Laurestinus shrub 
(Viburnum tinus) was well represented in places; and climbers like 
Smilax canariensis and Hedera canariensis were conspicuous. One 
cannot, however, pursue this subject here, and reference will now be 
made to another feature of the original evergreen forest, of which 
mention has not yet been made. 

The Large Size of the Trees in the Original Forests. — One 
can scarcely be surprised that authors, judging the past from the 
present, should write depreciatingly of the original forests of the 
Azores. Godman (p. 4) characterises them as " underwood " ; and 
Watson (p. 268), when alluding to their features, speaks of the 

frutescent and sub-arborescent " species, and of the " shrubs and 
small trees," of which they were composed. Hartung, who spent 
four months as a geologist in these islands in 1857, takes the same 
view in his book; but he depended mainly on Watson and Seubert 
for his botanical information, and made but few original observations 
except in the case of the buried Junipers. He was anxious to labour 
the point that the plants which are trees in the Canaries and Madeira 
become shrubs in the Azores; and he even rejected the adverse 
testimony of his buried Juniper trees, a subject discussed in a later 
page. A juster appreciation is given in Seubert' s work, which is 
based on the observations of the Hochstetters, where it is stated 
that plants such as Erica azorica, Laurus canariensis, and Myrica 
faya, which form bushes in the higher zones, grow as true trees in 
the lower woods. 

Deforestation at the hands of the woodcutters has been in progress 
for centuries, and in no localities more than in the woods bordering 
the roads or tracks, where only young trees grow. Visitors following 
the ordinary routes would thus only see young wood ; and the trees 



THE AZORES 



393 



growing in the woods farther back, often rendered difficult of access 
by a dense growth of brambles, would not come under their observation. 
This matter is discussed later; and it will be sufficient to point out 
here that in an ordinary traverse of the woods the trees would not 
be seen at their best. This is illustrated in Watson's conception 
of Myrica faya as a dense bush (p. 224) ; whereas, when allowed 
to grow undisturbed it becomes a tree of respectable size, thirty-five 
to forty feet high. 

Yet it is abundantly evident from the old Portuguese and other 
authorities of the sixteenth century quoted by Walker, such as 
Fructuoso, Cordeiro, and Linschoten, that the islands were once 
heavily timbered. In the middle of that century, according to 
Fructuoso, there were dense and lofty woods of Cedars (Juniperus), 
Fayas (Myrica faya), and Laurels (Laurus canariensis) on the slopes 
of the valley of the Furnas in San Miguel. Linschoten was resident 
in the group in the latter part of the sixteenth century. I have 
consulted his account as given by Purchas (edition of 1905). Writing 
of Terceira, he says that " the island hath great store and excellent 
kinds of wood, especially Cedar (Juniper) trees, which grow there in 
so great numbers that they make Scutes, Carts, and other grosse 
workes thereof." Of Pico he writes that it had " great store of wood, 
as Cedars and all other kinds, and also the costly wood Teixo (Taxus 
haccata). There they build many Carvels and small Ships; and 
from thence, by reason of the abundance of wood, they serve the 
other Islands with wood." It cannot, therefore, be doubted that 
Pico, as Walker observes (p. 84), was " at one time densely covered 
with timber of large size." 

In the early history of the Azores the timber of the Juniper trees, 
the " cedro " of the islanders, was extensively employed in building 
the churches. Walker (p. 252) quotes an early Portuguese authority 
to the effect that Terceira, when first discovered, was densely wooded 
with heavy timber, all the old churches and other buildings being 
roofed with " cedar " wood. Tradition has it that the immense 
beams even now in the roof of the cathedral at Angra were cut from 
trees that flourished as late as 1570. According to the same authority, 
the " last authentic record " of these " magnificent " Azorean Cedars 
being still in a flourishing condition relates to their use to repair 
a church at Villa Franca, in San Miguel, which was much damaged 
by the earthquake of 1630. In the church at Magdalena, on the 
island of Pico, which is said to have been built in 1710, a good deal 
of Cedar has been employed in the chancel, but it is now often gilded 
over. I learned from the priest that according to popular belief 
the wood came from Pico. It would seem from Walker's pages 
that most of the old timber trees in the group had disappeared before 
the close of the seventeenth century. 

Large Trunks of Trees buried in the Ashes of Ancient 
Volcanic Eruptions. — The trunks of trees overwhelmed in the 
early volcanic eruptions give similar testimony of the large size of 
the trees of the original forests. Frequent reference has been made 
by writers to their occurrence in the island of San Miguel. " From 
the boles occasionally unearthed at the Seven Cities and Furnas " 
(thus writes Walker, p. 25) " there is little doubt that these splendid 



394 PLANTS, SEEDS, AND CURRENTS 



trees, on its first discovery, inhabited a high belt of country extending 
east and west along the island." But very large trunks of other 
existing species of trees are also found buried in the volcanic tuffs 
of this island. Thus Walker (pp. 219, 220) refers to trunks of the 
Tree-Heath (Erica azorica) and of the Faya (Myrica faya) of giant 
proportions, which have been exposed in a state of lignite (?) in the 
ravines of San Miguel. So again, Carew Hunt, for years British 
Consul in the Azores and the principal source of Watson's later 
collections, when writing of San Miguel in the Journal of the Royal 
Geographical Society for 1845, states that there had been found in 
the tuffs trunks of the Faya, Juniper, and Tree-Heath, the Juniper 
with stems three feet in diameter. 

Most of the data concerning these buried trees relate to the Juniper 
or " cedar." When at Furnas in 1857, Drouet was shown an enor- 
mous semi-carbonised ( ?) trunk of Juniper oxycedrus, which indicated 
that formerly the trees attained a far greater size than they do to-day. 
It may here be said that this statement about the carbonisation 
of the wood is probably incorrect. In a letter to me Colonel Chaves 
emphatically denies the assertion of Walker, as above quoted, that 
buried trees in a state of lignite have been unearthed in San Miguel. 
The most important observations on these buried trees are, as he 
points out, those of Hartung, who says nothing about such a condition 
of the wood. It may be here apposite to give the results obtained 
by the German geologist as stated in his Die Azoren, Leipzig, 1860. 
He describes large trunks of the Juniper, that still grows on the 
island, as buried beneath great thicknesses of volcanic materials 
(blocks of tuff, pumice, and lava) heaped up during the later eruptions 
in the regions of Sete Cidades and the Furnas Valley in San Miguel 
(pp. 168, 200). In the Furnas Valley the thickness of the overlying 
material is stated to be about 400 feet, the date of the last eruption 
in that locality being 1660. The buried trunks of Juniper of the Sete 
Cidades are characterised as " machtige Baumstamme " ; and the 
diameters of two of them are given as two and an eighth and one 
and a half feet. In this connection Colonel Chaves writes to me 
saying that the biggest trunk of " cedar " (Juniper) found in the 
Azores is the trunk still remaining in the Grotta do Inferno at Sete 
Cidades. When referring to the Azorean Juniper, Trelease (p. 169) 
remarks that " large logs, apparently of this species, occur deeply 
buried under secondary volcanic debris in the Grotta do Inferno 
of the great crater known as Sete Cidades." 

I am indebted to Miss S. Brown, of " Brown's Hotel," Pont a 
Delgada, for some particulars relating to the buried " cedars " of 
Furnas, where she long resided with her father and brother. These 
buried trees were not uncommonly to be seen in the Furnas Valley ; 
but her father would never believe that trees of the large size indi- 
cated by the logs existed there, until he found the stump of one of 
these buried " cedars " showing the bases of the roots. It was 
found at a place called Alegria, at the north-eastern end of the 
valley. In a little sketch kindly supplied to me by his son, who 
was present at the time, this tree-stump is described as forty to 
forty-six inches high, with a diameter of twenty-four inches at its 
upper end, which apparently (as far as the sketch indicates) projected 



THE AZORES 



395 



originally about two feet above the ground. Miss Brown was good 
enough to send me a picture frame, made from one of these " cedar " 
logs, which her father had purchased. I sent it to the Kew Museum, 
and received through the kindness of Sir D. Prain the following 
report by Mr. Boodle, who examined the wood with care : " The 
wood appears to be that of a species of Juniperus, perhaps the same 
species as the block of wood in the Kew Museum, also dug up in 
the Azores. According to a label on this block, Masters states that 
Senor Henriques showed that this wood is identical with that of 
Juniperus brevifolia." In his letter to the author Sir D. Prain 
says : " I am prepared to accept his verdict as at any rate definite 
proof that the wood cannot be identified with anything but that of 
a Juniper." 

These buried Juniper trees have been also found in other islands 
of the group. When at Horta I was told by Mr. Keating that up 
to recent times the trunks were often dug up on Flores, and were 
used for building the small sailing craft trading between the islands. 
Writing of Terceira, Walker (p. 253) states that in various parts of 
the island " are occasionally found immense cedar trees embedded 
in deep ravines and valleys, still in perfect preservation." An 
unearthed log sometimes proved to be a godsend to the islanders, 
who promptly cut it up for firewood. 

The whole subject of these buried trees of the Azores requires 
systematic investigation; but there can be little doubt that the 
group possessed an abundance of excellent native timber in the 
early centuries of its occupation, and that it has none now. We 
would be unable in our days to find any native trees large enough 
to supply timber for the beams of the roofs of churches. Men, 
goats, and cattle have been active agents in deforesting these islands 
for four hundred years and more. Except when specially preserved, 
it would be difficult to find on Pico trees more than twenty feet 
high and more than thirty years old at the present day; and 
the same remark would apply to the native trees of the other islands. 

The Greatest Size attained by Existing Trees on the 
Azores. — Facts of the kind just given led me to inquire into the 
maximum size that the existing trees can acquire when unhindered 
in their growth; and it will be seen from the data to be now given 
that they can attain quite respectable dimensions, although falling 
far short of those indicated for the trees of the original forests. I 
took up the matter on the island of Pico. Land is there valued for 
the wood upon it, and it is profitable for the owner to leave his land 
undisturbed for many years. The great demand for wood for firing 
and other purposes usually prevents this being done; but in two 
of these " preserves " at the back of Magdalena opportunities were 
afforded me of investigating the subject. Here the larger wood 
was made up entirely of Myrica fay a, Laurus canariensis, and Erica 
azorica. The two first-named trees commonly attained a height of 
from thirty-five to forty feet and a diameter of from twelve to fifteen 
inches, and those of Erica azorica a height of twenty-five feet and 
a diameter of eleven or twelve inches. The Fay a trees occasionally 
exceeded forty feet, the maximum being fifty feet. In the gardens 
around Ponta Delgada they grow to a height of from thirty-five to 



396 PLANTS, SEEDS, AND CURRENTS 



forty feet. The Erica trees evidently need the protection of a wood 
to attain their maximum size. Though a few of them in these pre- 
serves must have measured between thirty and thirty-five feet, it was 
apparent from the number of leaning and fallen trees that this was 
their limit. 

It does not seem, however, that the present Juniper trees anywhere 
approach the size attributed to the " cedros " of the original forests. 
On Pico a height of fifteen or sixteen feet and a diameter of fifteen 
to eighteen inches (in very rare cases twenty inches) represent my 
maximum measurements. Rarely does the Azorean Juniper grow 
straight, the trunk being twisted and bent. It is likely that the 
finest specimens exist on the uplands of San Jorge. Judging from 
a photograph kindly taken in my interest by Colonel Chaves, they 
might there attain a height of eighteen or twenty feet. Mr. Ogilvie- 
Grant mentions the " grand old Juniper trees " in the higher levels 
of the same island (Novitates Zoologicce, XII., 1905). 

The Causes of the Destruction of the Original Forests. — 
That the volcanic eruptions of early times played an important part 
in the destruction of forests in the Azores is highly probable. The 
old timber trees, as before described, are now found buried beneath 
their ejectamenta. In the early part of the occupation by man, 
namely, in the fifteenth and sixteenth centuries, the devastation 
of the forests from this cause must have been tremendous, and it is 
likely that the older outbreaks produced similar results. Since 
pumiceous tuffs strew the surface of San Miguel and are often exposed 
in sections a hundred feet in thickness, both in the high and in the 
low levels, we cannot help reflecting that the land-surface at such 
times must have been largely deprived of its covering of vegetation. 
The outbreak that occurred in the valley of Furnas in 1630 well 
illustrates what must have often taken place before. For three 
days and nights the ashes fell over all the island of San Miguel, 
covering the surface to a depth ranging from seven to twenty feet, 
and in many places destroying all the vegetation (Walker, pp. 61, 
214). Even greater desolation must have resulted from the eruption 
of 1445, when the highest eminence of the island at its western end 
was destroyed, leaving the great crater of the Seven Cities as its 
mark (Ibid., pp. 51, 57, etc.). The adjacent seas were covered with 
fields of floating pumice and immense trunks of trees, through which 
Cabral, the Portuguese navigator, made his way when approaching 
the island. It is probable that in the relatively recent activity of the 
volcanic forces in the Azores we have an explanation of the curious 
fact referred to in a later page of this chapter, that of the three 
Macaronesian groups, the Azorean, the Madeiran, and the Canarian, 
it is the group that is farthest from the mainland, namely, the Azores, 
that displays the least evidence of differentiation in its flora. 

Yet it is likely that the plant world would have of itself regained 
much of its hold on the Azores, if it had not been for the arrival 
of the European. Man and his animals have completed the destruc- 
tion of the original forests. In fact, Colonel Chaves, whose opinion 
would carry the greatest weight, seeks for the exclusive factor in 
the disappearance of the forests in " the destruction made by the 
inhabitants for constructions, fire, and exportation " (letter cited). 



THE AZORES 



397 



The islands were discovered between 1432 (Santa Maria) and 1452 
(Flores), and the early settlers displayed much energy in clearing 
the forests. Goats, hogs, and cattle were soon introduced, and they 
doubtless effectively assisted man in " the rapid and total extinction 
of these grand denizens of the forest, and with them probably of 
interesting plant and insect life " (Walker, p. 25). It is stated 
that as early as 1526 the coasts of San Miguel were all under cultiva- 
tion, and that sixteen parishes and six villages had been founded. 
According to the Traveller's Guide to Michael's, by F. S. Mayor (pp. 18, 
19, Ponta Delgada, 1911), from which the facts just quoted have been 
taken, the earliest cultivation was of cereals and sugar-cane, the latter 
succumbing in 1560 to disease. From 1520 to 1640 great quantities 
of the Woad plant (Isatis tinctoria) were raised and exported ; and, 
as we learn from the same authority, flax was cultivated between 
1750 and 1764. In Linschoten's time (about 1589) the inhabitants 
of San Jorge, as they do at present, chiefly raised cattle and conveyed 
their produce to the islands near (see Purchas). One can imagine 
the extensive importation of weeds that must have been involved 
in the endeavours of the earlier colonists to develop the resources 
of the group. 

In the course of time, so rapidly was the clearing of the woods 
effected in the more populous islands, like San Miguel and Terceira, 
that they began to look to the other islands for their timber. Thus 
Flores supplied Terceira with " cedars," and Pico seems to have been 
from the earliest days of the occupation a source of timber for the 
neighbouring islands. Some of the most valuable woods were sent 
to Portugal in these early times. Thus Dr. Webster, whose descrip- 
tions of St. Michael was published in 1821, states that considerable 
quantities of " the wood of Pico," apparently a species of yew, 
were formerly sent to Lisbon, where it was manufactured into work- 
tables, desks, etc. 

Whilst the earlier colonists despoiled their timber forests for 
erecting their houses, churches, and for similar purposes, they also 
employed the timber for firewood. Linschoten writes that in his 
day, namely, in the latter part of the sixteenth century, the wood 
of the " cedar " (Juniper) " is the commonest wood that they use 
to burne in those Countries, whereby it is the wood that with them 
is least esteemed, by reason of the great quantity thereof " (Purchas, 
vol. 18, p. 366). This practice has continued down to more recent 
times. The Bullars state that the " small stunted cedars " were 
so common on Flores in their time (1839) that their wood was used 
for heating the ovens, the pleasant smell from the cedar smoke 
of the cottage fires being noticeable outside the houses. In Pico 
at the present day the wood of the Juniper is extensively employed 
for the staves and bottoms of the milk buckets. 

The need of fuel through the centuries and the requirements for 
fruit-boxes in later times have sealed the fate of the original forests. 
The demands of the fruit-trade were so great that at the time of 
which Walker wrote, about 1880, trees fifty years old were seldom 
met with on San Miguel. Those demands have passed away with 
the trade; but the need for fuel is of course insistent. Pico has 
been for generations the principal source of fuel for the neighbouring 



398 PLANTS, SEEDS, AND CURRENTS 



island of Fayal. At present a regular trade in Pico firewood exists 
between Horta and the towns and villages on the Pico side of the 
straits. There is but little attempt in the way of re-foresting the 
island of Fayal. Writing of a time so long ago as 1839 the Bullars 
remarked that " to such an extent has this short-sighted destruction 
been carried in Fayal that, with ample room for plantations, the 
principal supply of fuel is derived from Pico " (II., 8). 

Firewood is the eternal question with these people ; but it is only 
used for cooking their food, the foliage serving as fodder, the leafy 
branches as litter in their stables, and the branches of the Ling 
(Calluna vulgaris) and the Tree-Heath {Erica azorica) as brushwood. 
The procuring of these materials seems to be one of the principal 
occupations of their lives. On the lower slopes of the great mountain 
of Pico one meets all through the year a constant string of men, 
women, and bullock-drawn carts carrying loads of Erica azorica, 
Calluna vulgaris, Myrica faya, Laurus canariensis, Ilex perado, etc., 
the foliage of the last-named plant being cut in quantity for mule 
fodder. Withal, there is no attempt at renovation of the sources 
of supply. The land is allowed to remain undisturbed for several 
years, and the owner makes considerable profit by selling it with 
the wood standing, receiving it back when the wood is all felled. 
Faya trees attain a diameter of five or six inches in from eight to 
ten years, so that the growth of one of the most abundant and most 
useful of the trees can scarcely be said to be very rapid. 

The lower wooded slopes of the mountain of Pico reaching to the 
government lands, 3000 to 4000 feet above the sea, are all private 
property. Low walls of loose lava blocks separate the different 
Ownerships, the poor man having a small patch and the rich man 
a large one. These properties are handed down from parents to 
children, and the rights are rigidly observed. They may remain 
in the same family for generations. A bequest of a small patch of 
woodland for some poor widow is as much a necessity of her existence 
as a dwelling, and willing hands help her to bring the faggots down 
the mountain side, if she is old and feeble. A large amount of the 
carrying is done by the women, whilst the men do the felling. Coal 
at my time was only used by some of the better-class Picoese. The 
poorer people of the larger coast towns, like Magdalena, usually 
purchased their wood off the land from the owner, felled it themselves 
and carried it home, about six dollars' worth lasting them a year. 

The Affinities of the Native Flora of the Azores. — The 
characteristic flowering plants of the woods, of the moors, of the 
ponds and lakes, and of the coast, exhibit in a progressive scale a 
gradually extending connection with the outer world. This is well 
brought out in the tables following these remarks. Whilst the shrubs 
and trees of the woods are for the most part non-European, and 
either exist in the other two Macaronesian groups (the Canaries 
and Madeira) or are represented there by closely related species, 
the plants of the upland moors and of the ponds and lakes are nearly 
all European species, that rarely occur either in the Canaries or in 
Madeira. The shore plants on their part are fairly well distributed, 
both in Europe and in the other two groups; and nearly half of 
them are also North American. The North American connections 



THE AZORES 



399 



of the native flora are almost all of them European species; and, 
as might be expected from what has been said above, they are least 
evident with the plants of the woods and most pronounced amongst 
those of the sea-border and of the ponds and lakes. 

The restrictions of most of the characteristic plants of the woods 
to the Macaronesian islands, the extension of nearly all those of 
the upland moors to Europe, and the common dispersion on both 
sides of the Atlantic of the plants of the seashore and of the ponds 
and lakes, illustrate a principle of wide application to insular floras — 
a principle, however, that is often best exemplified in tropical regions. 
The varying degrees of isolation thus implied reflect, as will be shown 
later on, the differences in the histories of the dispersing agencies 
in stocking with their plants the woods, the moors, the ponds and 
lakes, and the seashores. The currents have been for ages unceas- 
ingly at work, directly and indirectly, in carrying seeds from one 
coast to another; and as a rule in tropical latitudes the specific 
connections kept up between the shore floras of different regions 
can be mainly ascribed to their influence. In a similar manner 
migrant waterfowl have sustained the connections of the plants 
of the river, the lake, and the pond, over great areas of the globe. 
In a like fashion, though to a less extent, birds of the grouse family 
have kept the plants of the mountain moors of distant regions in 
touch with each other. On the other hand, the dispersing activities 
of forest-frequenting birds, as far as oceanic islands are concerned, 
have been more and more restricted in the course of ages. The bird 
finally comes to stay, and both plant and bird differentiate together. 

The foregoing subject is dealt with in the penultimate chapter 
of my book on Plant Dispersal ; but it is one, the importance of 
which was long since recognised by Godman in his work on these 
islands (p. 339). The principles involved have been unable to find 
their full expression in the islands of the Azores by reason largely 
of the lesser antiquity of those islands as compared with such an 
ancient group as that of the Hawaiian Islands in mid-Pacific. There, 
the impress of a far greater antiquity lies on the flora, and where 
species have been differentiated in the Azores genera have been 
developed in Hawaii. As shown in the work above named, it is 
on the forested mountain slopes of the Hawaiian Islands that most 
of the peculiar genera and peculiar species, both of plants and birds, 
are to be found. Here the agencies of trans-oceanic dispersal have long 
since ceased to act. A later suspension of these agencies is indicated 
by the plants of the mountain moor, which are generically connected 
with regions on both sides of the Pacific, but are usually specifically 
distinct. Yet, unless within recent times, there has been no suspen- 
sion in the activity of migrant waterfowl as seed-carriers to the 
Hawaiian group, and as a result we find in the waters and at the 
sides of ponds and rivers plants that are widely distributed over the 
world. Lastly, there are the beaches, where, through the action 
of the currents in the run of the ages, we find several of the littoral 
plants characteristic of the tropical shores of Malaya, continental 
Asia, Africa, and America. We thus perceive that the Azorean 
and Hawaiian floras exhibit the same progressive scale of connections 
with the outer world, which are least with the plants of the woods, 



400 PLANTS, SEEDS, AND CURRENTS 



freer with the plants of the upland moor, and more or less unrestricted 
with the aquatic plants and with the plants of the seashore. 

Though the contrasts in the differentiation of the Azorean and 
Hawaiian floras are largely bound up with the differences in the 
antiquity of the two archipelagos, the much greater isolation of the 
Hawaiian group, which lies some 2000 miles from the nearest main- 
land, has doubtless had a potent influence. Yet antiquity alone may 
largely counteract the effects of contiguity to a continent. The 
Canaries, for example, are evidently of much greater age than the 
Azores, and to this circumstance we might attribute the fact that 
as many as 30 per cent, of their native plants are peculiar, whilst 
only 10 per cent, are endemic in the Azores. Yet only fifty-five 
miles of open sea separate the Canaries from the African coast, 
whilst about 800 miles intervene between the Azores and the nearest 
mainland, the coast of Portugal. So with the Galapagos Islands, 
which are removed about 500 miles from the coast of Ecuador, half 
of the native plants are endemic. It is therefore evident that an 
influence more potent than that concerned with distance from the 
mainland may affect the endemism of some insular floras. Presum- 
ably this is often that of antiquity. 

Before proceeding with the discussion of the affinities of the native 
flora of the Azores, I will give in tabulated form the distribution 
of the most characteristic plants grouped according to their station. 
The affinities of the individual groups will then be dealt with, and 
this will be followed by a comparison of the Azorean, Madeiran, and 
Canarian floras, as far as it can be focussed in a contrast of the vegeta- 
tion of the Peak of Teneriffe and of the great mountain of Pico. 

Distribution op Characteristic Native Flowering Plants op the 
Azores outside the Group 

I 

Plants of the Woods 





Canaries 


Madeira 


Africa 


Europe 


North 
America 


Remarks 


Hypericum foliosum 
(Ait.) 












Probably allied to a 
species of Madeira, 
H. grandifolium. (See 
Watson.) 


Ilex perado (Ait.) 


+ ? 










Allied to a Canarian 
species, if not in the 
group (Watson). 


Phamnus latifolius 
(Herat.) 




+ 








Lowe is the authority 
for its Madeiran habitat. 


Primus lusitanica (L.) 


+ 


+ 




+ | 




Rubusfruticosus (L.) 


+ 


+ 


+ 


+ 




A segregate species 
usually named discolor 
by English botanists 
(Watson). (SeeTrelease.) 



THE AZORES 401 



Plants of the Woods (cont.) 





Canaries 


Madeira 


Africa 


<£> 
Pi 
O 

u 


North 
America 


Remarks 


Hedera canadensis 
(Willd.) 


+ 


+ ? 








Near H. helix (Wat- 
son). 


i Arceuthobium oxy- 
cedri (M.B.) 






+ 


+ 


+ 


The authorities for its 
distribution are the In- 
dex Kewensis and Arc- 
angeli's Flora Italiana. 


Viburnum tinus (L.) 






+ 


i 

T 




Trelease describes the 
Azorean form as a 
variety of V. tinus under 
the name of subcordatum. 


Vaccinium cylindra- 












Closely allied to a 
Madeiran species V. 
maderense. (See W at- 
son.) 


Erica azorica 
(Hochst.) 














Picconia excelsa 
(DC.) 












Notelcea excelsa (W T ebb) 
is a second name. 


Myrsine africana (L.) 






+ 






Widely distributed in 
Africa and Central Asia. 


Daphne laureola (L.) 






+ 


+ 






Laurus canariensis 
(Webb) 


+ 


+ 








The Pevsea azorica of 
Seubert. 


Persea indica (Spr.) 




+ 








Laurus indica in 
Lowe's work. 


Euphorbia mellifera 

t Alt. ) 




+ 








The Azorean variety 
is Styc/iana ( Watson). 


Smilax 


+ 










Trelease divides the 
Canariensis of Watson 
into Excelsa, L., and 
Divaricata, Sol. 


Myrica faya (Ait.) 




+ 










Juniperus brevifolia 
(Hochst.), a var. of 
J. oxycedrus (L.) 


+ 


+ 


+ 


+ 




Seubert's view that 
J. brevifolia stands to 
J. oxycedrus as J. nana 
to J. communis is 
adopted. The distri- 
bution given is that of 
J. oxycedrus. 


Taxus baccata (L.) 






+ 


+ | + 


Lowe is the authority 
for its being Madeiran. J 



D D 



402 PLANTS, SEEDS, AND CURRENTS 



Distribution of Characteristic Native Flowering Plants of the 
Azores outside the Group (cont.) 



II 

Plants of the Upland Moors 





Canaries 


Madeira 


Africa 


Europe 


North 
America 


Remarks 


Viola palustris (L.) | 






1 

+ 


+ 1 


1 


Polygala vulgaris (L.) 








+ 






Potentilla tormen- 
tilla (Wats.) 




+ 




+ 






Hydrocotyle vulgaris 
(L.) 








+ 






Calluna vulgaris (S.) 






+ 


+ 


+ 




Menziesia polifolia 
(Sm.) 








+ 






Erythrsea massoni 
(Sw.) 












Connected by some 
with a Canarian species. 


Sibthorpia europaea 
(L.) 






+ 


+ 




Occurs in the Abys- 
sinian highlands 
(Hooker's Marocco, p. 
422). 


Thymus serpyllum 
(L.), var. angusti- 
folius (Bois.) 




+ 


+ 


+ 




The distribution re- 
ters to the species. 


Lysimachia nemo- 
rum (L.) 








+ 




The separation of L. 
azorica (Hornem.) is not 
here adopted. 

Though regarded as 
distinct species by both 
Watson and Trelease, 
they are united in the 
Index Kewensis and by 
Seubert as well as by 
Pax and Knuth in the 
Pflanzenreich. 


Anagallis tenella (L.) 






+ 


+ 






Luzula purpureo- 
splendens (Seub.) 














Car ex flava (L.) 




+ 




+ 


+ 


Also Asiatic. 



THE AZORES 



403 



Distribution of Characteristic Native Flowering Plants of the 
Azores outside the Group (cont.) 

Ill 

Plants of the Ponds and Lakes 





Canaries 


Madeira 


Africa 


Europe 


North 
America 


Re marks 


Callitriche aquatica 
(L.) 






+ 


+ 


+ 


World-wide. 


Peplis portula (L.) 






+ 


+ 




Littorella lacustris 
(L.) 








+ 






Potamogeton poly- 
gonifolius (Pourr.) 






+ 


+ 


+ 


Also Asiatic. 


Scirpus palustris (L.) 


+ 




+ 


+ 


+ 


Also Asiatic. 


Scirpus multicaulis 
(Sm.) 








+ 






Scirpus fluitans (L.) 








+ 






Scirpus savii (S. and 
M.) 






+ 






Watson is here fol- 
lowed. Ball gives it as 
on the Great Atlas. 


Carex stellulata 
(Good.) 








+ 


+ 1 


Also Asiatic, Aus- 
tralian, etc. 



404 PLANTS, SEEDS, AND CURRENTS 

Distribution of Characteristic Native Flowering Plants op the 
Azores outside the Group (cont.) 

IV 



Plants of the Sea-coasts 





Canaries 


Madeira 


Africa 


Europe 


North 
America 


Remarks 


Cakile edentula 
(Bigel.) 




+ ? 






+ 


For Madeira see page 
185. Probably intro- 
duced into Azores in 
ballast. 


Silene maritima (B. 
and H. Handbook) 


+ 


+ 




+ 






Spergularia marina 
\ w arson ) 


+ 






+ 


+ 


Also Asiatic. 


Mesembryanthe- 
mum ? 












See page 384. 


Crithmum mariti- 
mum (L. ) 


+ 


+ 


+ 


+ 






Solidago sempervi- 
rens (L. ) 










+ 


Also indigenous in 
Bermuda. 


Campanula vidalii 
\ vv arson ) 












See page 427. 


ErytnrsBa maritima 
(Pers.) 


+ 


+ 




+ 






Ipomcea carnosa (R. 
Br.) 








+ 




Occurs also in the 
Hawaiian Islands. 


Hvoscyamus albus 
(L.) 


+ 


+ 


+ 


+ 






Plantago coronopus 
(L.) 


+ 


+ 


+ 


+ 






oaisoia Kali [it.) 




+ 


+ 


+ 


Also Asiatic. 


Beta maritima (L.) 


+ 


+ 


+ 


+ 






Polygonum mariti- 
mum (L.) 


+ 


1 

+ + 


+ 


+ 




Euphorbia azorica 
(Hochst.) 




+ ? 




+ ! 




In De Candolle's Pro- 
dromus regarded as a 
variety of E. pinea, 
L., which occurs in 
South Europe, North 
Africa, and Madeira. 


Euphorbia peplis (L.) 


+ 






+ 






Juncus acutus (L.) 


+ 


+ 




+ 


+ 





Note. — With one or two exceptions the African localities are North African, though 
several of the plants have a wider distribution in the continent. 



THE AZORES 



405 



Summary of the results given for the characteristic plants of the 
Azores in the foregoing tables. 





Macaronesian 
exclusively- 


a 


a 

cS 


North American 


Remarks 




Total 


Peculiar 
to Azores 


Africa 


Europ 


Plants of the woods 
(total 20) 




3 


7 


7 


2 


Two of the peculiar 
Azorean species are 
closely allied to Ma- 
deiran species. 


Plants of the upland 
moors (total 13) 


2 


2 


4 


11 


3 




Plants of the ponds 
and lakes (total 9) 








5 


9 


4 




Plants of the sea- 
coast (total 15) 


1 


1 


7 


13 


6 


The species of Cakile 
and the doubtful species 
of Mesembryanthemum 
are not included. 



Note. — Macaronesia is here taken as comprising the Azores, the Madeiras, and the 
Canaries. The total under this head includes not only the Azorean plants occurring 
in the Canaries and Madeira (one or both), but also the peculiar Azorean plants 
which are indicated in the next column. 

With one exception the African localities are North African, though several of the 
plants have a wider distribution in the continent. 

(A) The Affinities of the Characteristic Plants of the Woods. — Although 
the ancestors of the non-European species were in all probability 
originally derived from Em-ope, they doubtless belong to an early 
period in the plant-stocking of the group, the connection with their 
home having been long since broken off. But this rupture has only 
affected the majority of the plants, about a third of those named 
in the foregoing list being European species. Three of them, Daphne 
laureola, Viburnum tinus, and Juniperus occycedrus, grow on the slopes 
of the Great Atlas at altitudes of 4000 to 6500 feet (Ball), whilst Taxus 
baccata is at home in the mountains of Algeria (Arcangeli). 

The possibility thus presents itself that the Azores derived some 
of their European plants by way of the mountains of North-west 
Africa. But there is reason for the belief that the other two Maca- 
ronesian groups, the Canaries and the Madeiras, have received 
similar accessions to their floras from the Atlas Mountains. Thus, 
to take the Canarian forest flora, we have in Daphne gnidium a 
European species that is associated on the slopes of the Great Atlas 
with Daphne laureola, and in Viburnum rigidum a species which 
from its resemblance to the Azorean variety of V. tinus might be 
by some regarded as possessing the same parentage (see on this 
point Trelease, p. 118). Then again the Canarian flora owns in 



406 PLANTS, SEEDS, AND CURRENTS 



Juniperus oxycedrus a Great Atlas tree. Not more than 250 miles 
separate the western extreme of the Atlas Mountains from the Canary 
Islands, and it would be strange if the woods of that archipelago 
had not received important accessions from that elevated region. 
Much of what has been said of the Canarian forest flora would apply 
also to Madeira. In this case the Yew (Taxus baccata) and the 
Juniper (J. oxycedrus) could have found their nearest source in the 
Western Atlas. 

As regards the possibility of the Azorean woods having received 
some of their European species from North-west Africa as well as 
from South-west Europe, one may be prepared for much when we 
reflect on the very singular African connection displayed by one 
of the most predominant of the shrubs, namely, Myrsine africana. 
It is a native and often a mountain plant of Inter-tropical and South 
Africa, Arabia, and Central Asia. It is not even at home in Madeira 
and the Canary Islands, its nearest known habitats being in Angola 
and Abyssinia. Its small berries are well suited for dispersal by 
frugivorous birds; but its isolated occurrence in the Azores is one 
of the puzzles of the flora. 

But by far the most important feature in the affinities of the 
characteristic plants of the Azorean woods is indicated in the fact 
that, whilst mainly non-European, they are largely Canarian and 
Madeiran. We are not so much concerned here with statistical 
results, such as are presented at the end of the previous table, but 
with the fact that with one exception, that of Myrsine africana, 
all the trees and shrubs that are most abundant are either Canarian 
or Madeiran, or are presented in one or both of those two groups 
by closely allied or similar species. They are Canarian in a special 
sense, since they are for the most part confined to the middle zone 
or Laurel belt of Teneriffe, which lies between the levels of 2000 and 
5000 feet. That their general facies was Canarian was recognised 
by the writer when exploring the Azorean woods, after a previous 
acquaintance on Teneriffe with the woods situated between 2000 
and 3000 feet above the sea in the Laguna and Taganana districts. 
In these Canarian woods flourish the same two Laurels, Laurus 
canariensis and Per sea indica, the same species of Myrica (M. fay a), 
a similar Tree-Heath (Erica arborea), a Holly closely allied to or 
identical with the Azorean Ilex (I. per ado), allied species of Rhamnus, 
Vaccinium, and Viburnum, and among the climbers the same species 
of Hedera and Smilax. Excluding the special Canarian element, 
the list given by Christ of the characteristic trees and shrubs of the 
Laurel woods of Teneriffe might in most respects pass for one of 
those of the Azorean woods on the slopes of the great cone of Pico ; 
but this is a subject that will be again noticed when we compare 
the zones of vegetation on the slopes of these two great volcanic 
mountains. 

The Madeiran aspect of the Azorean woods is seen in many ways. 
Here again, after excluding the special Madeiran element, the principal 
indigenous trees and shrubs named by Lowe for the lower woods 
and for the Laurel and Heath zone, 2500 to 5500 feet above the sea, 
include many of those that give character to the Azorean woods. 



THE AZORES 



407 



Here in the lower woods are Myricafaya, Rhamnus latifolius (now very- 
rare), and Euphorbia mellifera, as well as a representative species 
of Hypericum (H. grandifolium). In the upper woods grow Laurus 
canariensis, Persea indica, Ilex perado, Picconia excelsa (now very 
rare), a representative Tree-Heath {Erica arbor ea), and a species 
of Vaccinium (V. maderense) closely allied to the Azorean species. 
The thickets of Tree-Heath and of Vaccinium, in which thrive the 
two Madeiran Hollies (Ilex perado and /. azevinho), must together 
with the Laurels and the Fayas often give an appearance very 
Azorean to the remains of the original Madeiran woods. We will 
now proceed to discuss briefly the affinities of the other groups of 
characteristic Azorean flowering plants. 

(B) The Affinities of the Characteristic Plants of the Upland Moors. — 
Of the thirteen plants named in the list eleven are European and two 
are endemic. There is no African or North American connection 
that is not also European. There are seemingly hardly any of these 
plants in the Canaries and not many in Madeira; and when we 
reflect that only Thymus serpyllum appears to be represented on 
the Great Atlas range, namely, on the higher slopes, we are driven 
to the conclusion that the Azores derived their moor plants from 
Southern Europe. 

(C) The Affinities of the Characteristic Plants of the Ponds and' 
Lakes. — The conclusion formed for the plants of the moors applies; 
here with greater force. All the species are European, and this 
disposes of any special connection either with Africa or North 
America. Then, again, few of them have been found either in Madeira 
or in the Canaries. We must therefore look to South-western Europe 
for the source of the Azorean aquatic and subaquatic plants. 

(D) The Affinities of the Characteristic Plants of the Sea-coast. — 
Here, though predominantly European, the species are well repre- 
sented in North America as well as in the Canaries and Madeira., 
though, if we exclude Cakile edentula, which was probably introduced 
in ballast, the only North American species that is non-European 
is Solidago sempervirens. The case of Campanula vidalii probably 
raises other issues. As concerns Euphorbia azorica it would be safer 
to give it a varietal value than to regard it as a distinct species. 

A Comparison of the Zones of Vegetation on the Great 
Cone of Pico with those on the Peak of Teneriffe and on the 
Island of Madeira. — The contrasts between the zones of vegetation 
in the Azores and the Canary Islands can be focussed in a comparison 
between the great mountain of Pico and the Peak of Teneriffe. 
The differences between the zones on Teneriffe are so striking that 
all observers agree fairly well in their accounts of them, whether 
in the case of Von Buch in the early part of last century or in that 
of Christ in the latter part of it ; and since the present writer made 
acquaintance with the plants of the lower two zones during a short 
visit to the island in the month of February, he is able to approach 
the subject with some confidence. 

The lowest zone on Teneriffe, the region below the clouds (as 
Christ designates it), reaches up to 2000 or 2500 feet. It is the 
African zone with all its strange-looking plants, the region of steppe 



408 PLANTS, SEEDS, AND CURRENTS 



vegetation. On its rocky slopes bushes prevail. Here we see the 
Cactoid Euphorbias, the curious rubiaceous Plocama pendula with 
the habit of a Casuarina, many shrubby Composite, such as Kleinia 
neriifolia, as well as several kinds of boragineous plants of the genus 
JEchium and a score of species of Statice. Here the Canarian palm 
^Phoenix canariensis) is at home ; but probably next to the Cactoid 
Euphorbias the Dragon-trees (Dracaena draco, dealt with in Note 31 
of the Appendix) gave most character to the larger vegetation in the 
early days. Amongst the most conspicuous and interesting of the 
lesser plants are the fleshy-leaved Crassulaceoz. On the steep slopes 
of the barrancos and on the faces of the lofty coast-cliffs they present 
themselves often as large flat rosettes that may measure as much as 
twelve or even fifteen inches across. Nowhere else in the world, 
writes Hemsley in his account of Christ's investigations, is there 
such a concentration of this class of plants, no fewer than fifty-two 
species having been enumerated by Christ, mostly belonging to the 
genus Sempervivum. 

Then follows, between 2000 and 5000 feet, the region of clouds 
and of rains, the zone of the Laurel forests, where we notice several 
Azorean trees and shrubs, such as Laurus canariensis and Persea 
indica among the Laurels, as well as Myrica faya, Picconia excelsa, 
a similar Tree-Heath (Erica arborea), and the same or allied or 
representative species of Ilex, Rhamnus, Smilax, Viburnum, and 
Vaccinium. Amongst the several trees and shrubs that are not 
found in the Azores are the two Laurels, Oreodaphne foetens and 
Phoebe barbusana, a species of Arbutus, and a species of the American 
genus, Clethra. The American elements in the Canarian flora will 
be again alluded to. 

Above the Laurel woods we enter the Pine belt, which is most 
characteristic of the levels between 5000 and 6500 feet. This was 
also the zone of the Juniper, now, as Christ remarks, almost exter- 
minated on Teneriffe. It is highly probable that the Juniper 
(Juniperus oxycedrus) was once associated with the Pine (Pinus 
canariensis) in considerable quantity; but the value placed on its 
timber, not only by the colonists but also by the aborigines, has 
resulted, according to Christ and others, in its practical extinction. 
However, scattered individuals still exist in the upper portion of 
the Pine belt; but it is extremely probable that it had originally 
much the same range as the Pine. It would seem that it still 
exists at altitudes of about 4000 feet on Palma, another island of 
the group, and that it once grew near the summit of one of the highest 
peaks of the island, the Pico del Cedro, which rises 7470 feet above 
the sea (see Bolle as quoted by Christ, and Samler Brown's Guide 
to the Canary Islands, 1905, pp. 1, 10). We might expect that the 
original vertical range of Juniperus oxycedrus on Teneriffe was 
about a thousand feet higher than it is on the slopes of the Great 
Atlas, about three degrees farther north, where it was placed by 
Hooker and Ball (p. 433) at 4000 to 6500 feet. 

Beyond the Pine belt is a belt covered with the " codeso " (Adeno- 
varpus viscosus), a leguminous shrub that extends to about 7000 feet. 
This plant then gives place on the pumice-stone plains of the Canadas 



THE AZORES 



409 



to the " retama " (Spartocytisus nubigenus), a broom, which with 
occasional herbs reaches to nearly 11,000 feet. So characteristic 
is the broom of this elevated region that the pumice plains are known 
as the " Llano de la Retama." 

Before contrasting the zones on Teneriffe with those on Madeira 
and in the Azores, we will first determine what we ought to expect, 
having regard to the difference in latitude (Teneriffe, 28° 17' N. ; 
Madeira, 32° 44'; Pico, 38° 28') and the associated differences in 
climate. From the data given below it will be apparent that in 
response to the cooler climatic conditions we should expect in the 
case of Pico no African zone, and in its place the extension of the 
Laurel woods to the coast. In the case of Madeira we should look 
for intermediate features in the vertical range of the zones. The 
African zone would be considerably restricted, and the lost ground 
would be occupied by the Laurel woods in their descent towards 
the coast. 

Taking the rate of change of the mean temperature at rather over 
three degrees, Fahrenheit, for each thousand feet, the difference in 
the annual mean temperature near the sea-level at Teneriffe and 
Pico, which is about seven or eight degrees (69-61), would represent 
some 2000 or 2500 feet. From this it follows that the warm climatic 
conditions that prevail below 2000 or 2500 feet on Teneriffe, or, in 
other words, those of the African zone, would not exist on Pico; 
whilst the Laurel woods, which succeed the African zone on Teneriffe, 
would on Pico descend to the coast. In the case of Madeira, where 
the mean annual temperature near the sea-level (about 66° F.) is 
some three or four degrees lower than at Teneriffe, the corresponding 
difference in altitude would be 1000 or 1200 feet. As the result, 
the upper limit of the African zone in Madeira, instead of lying 
2000 or 2500 feet above the sea, as on Teneriffe, would only attain 
half that elevation on the Madeiran slopes, and the Laurel woods 
would descend to a similar extent. 

When we come to the facts, and compare in the first place the 
zones of vegetation on Teneriffe and on Pico, the results may soon 
be stated. Pico owns no African zone. Where the cultivator has 
allowed it, its lower woods so Canarian in their character, in their 
Laurels, their Fayas, and their Tree-Heaths, instead of lying some 
2000 or 2500 feet up the slopes, as on Teneriffe, descend to the vicinity 
of the coast. So also its upper woods, where the Azorean repre- 
sentatives of the Canarian Juniper (J. oxycedrus) give character to 
the vegetation, indicate a similar downward displacement of some 
2000 feet or more, as compared with the elevation of the original 
Juniper zone on Teneriffe. The Canarian Juniper zone evidently 
lay above 4000 feet; whilst the Azorean zone of Junipers descends 
to 2000 feet. 

But there is no belt of Pines on Pico. It cannot be argued that 
the suitable soil- conditions and the requisite elevation for the genus 
would not be found on the barren slopes of lava and cinders on the 
higher levels of the mountain, since from the association on Teneriffe 
of the Canarian Pine with Juniperus oxycedrus it is apparent that 
the place of the Pine on Pico would be at elevations 2000 or 2500 



410 PLANTS, SEEDS, AND CURRENTS 



feet lower than on Teneriffe, that is to say, between 2500 and 4500 
feet above the sea. Here, usually under good soil-conditions, the 
Juniper is at home on Pico, but there are no Pines. The absence 
of the Pine from Pico, and from the Azores as a group, is a very 
pregnant fact in the history of the plant- stocking of the archipelago. 
A brief comparison of the summit vegetation of the great volcanic 
mountains of Teneriffe and of Pico, as well as of Madeira, will follow 
the description of the zones of vegetation on the last-named island. 

In the case of Madeira, sufficient materials for the comparison of 
its zones of vegetation are supplied by Lowe. The lowest or tropical 
zone, corresponding to the African zone on Teneriffe, extends accord- 
ing to this authority only 700 feet up the slopes. He names it the 
Cactus and Banana zone, and names among its indigenous plants 
Draccena draco and Euphorbia piscatoria (the Dragon Tree and arbores- 
cent Euphorbia of the lowest Canarian zone), with species of Semper- 
vivum, and the sapotaceous tree, Sideroxylon mermulana ; but we 
may infer that both in its extent and its characters the lowest 
Madeiran zone is a poor representative of the Canarian zone. From 
the data given by Lowe we can infer that the woods which originally 
clothed the slopes of Madeira from five or six hundred feet above the 
sea to within a few hundred feet of the summit, the altitude of which 
is about 6100 feet, were in the main the representatives of the Laurel 
woods of Teneriffe, which there exist at levels of 2000 to 5000 feet. 
In their lower levels flourished, as in the Azores, the Faya tree (Myrica 
fay a), and in the upper levels the Azorean Laurels Laurus indica and 
L. canariensis), all characteristic of the Canarian woods. They were 
associated with the Tree-Heath (Erica arborea) of Teneriffe, Rhamnus 
glandulosa of the same island, the Tree-Euphorbia (E. mellifera), 
and Picconia excelsa of the woods of Pico and Teneriffe, besides 
shrubby species of Hypericum and Vaccinium, representing pre- 
dominant plants of the Azorean and Canarian woods. But a feature 
of the Madeiran as well as of the Canarian woods, a feature not 
possessed by those of the Azores, is the presence of shrubs and trees 
of the American genera, Clethra, Cedronella, and Bystropogon, etc., 
to the significance of which allusion will subsequently be made. 

There was originally a Juniper zone in the higher levels of the 
Madeira woods, such as there was once on Teneriffe, and such as 
exists now on Pico. Though now nearly exterminated on account 
of the value set on its timber, Juniperus oxycedrus, as Mr. Johnson 
tells us (Encycl. Brit. 9th edit. XV., 180), was formerly abundant, 
and grew to a height of forty or fifty feet. Its lower limit was pro- 
bably intermediate between that of the Juniper zone on Pico (2000 
feet), and on Teneriffe (4000 feet), so that probably it would have 
flourished at levels above 3000 feet. Walker, in his book on the 
Azores, speaks of this Juniper as growing to a stately size in the 
mountain fastnesses of Madeira. Indigenous Pines are absent from 
Madeira as well as from the Azores, and the same difficult question 
is here raised. Since Pinus pinaster has been extensively planted 
on the Madeiran slopes, the absence of the genus cannot be due to 
unsuitable conditions. 

It is remarkable that whilst the woods of Pico, Madeira, and 



THE AZORES 



411 



Teneriffe possess many features in common, the plants that have 
found a home on their summits differ greatly. We have seen that 
the plants which have reached the summit of the great cone of Pico, 
the Heather (Calluna vulgaris), the Heath (Menziesia polifolia), the 
Thyme (a variety of Thymus serpyllum), the grasses, etc., have all 
climbed up from the moors below. This would have been impossible 
either on Teneriffe or Madeira, on account of the absence of moors 
of this description. Yet in the queer little gathering of half a dozen 
native plants, which Lowe describes as having found a refuge on 
the rocky crags of the summit of Madeira, there is a small effort 
in this direction. After removing from his list Cerastium tetrandrum 
(Curt.), as probably an introduced weed, there remain Arenaria 
serpyllifolia, Erica cinerea, Viola paradoxa, Armeria maderensis, 
and Avena marginata, the three last being first described by Lowe 
as peculiar to the island. Coming to the scanty vegetation of the 
high levels of Teneriffe, it is to be again observed, that apart from 
the perennial herbs (Arabis albida, etc.) it is the Retama broom 
(Spartocytisus nubigenus) that gives a character to the pumice-stone 
plains of the Canadas between 7000 and 9000 feet above the sea, 
a leafless shrub that climbs the steep lava slopes of the terminal 
cone to a height of 11,000 feet. The history of the Retama in this 
elevated area is implied in a remark of Hooker, that its Moorish 
name has come to be used by botanists for a small group of brooms, 
containing a few nearly allied species, that are widely spread through- 
out the region extending from Spain to the Canary Islands (Marocco 
and the Great Atlas, p. 27). A Violet, known as Viola teydensis and 
peculiar to the peak, clings to the soil at the upper edge of the Llano 
de la Retama, as the pumice-stone plains are called. Above this 
level, writes Johnson (Encycl. Brit. 9th edit. IV., 797), there is nothing 
but a little lichen. 

We have remarked that the peculiar feature of the summit vegeta- 
tion of the great cone of Pico, as compared with the Peak of Teneriffe 
and with Madeira, is that it is all derived from the moors below. 
This brings us to another distinctive feature in the zones of Pico. 
The wet and dry moors, which are so conspicuous around the middle 
levels of the mountain of Pico, having been formed at the expense 
of the upper woods or the Juniper zone, seem scarcely represented 
on Teneriffe and Madeira, hardly any of their characteristic plants 
being there present. This contrast is well reflected in the differences 
in the Sphagnum floras of the three groups, as brought out in Warn- 
storf's monograph on the Sphagnaceaz (Das Pflanzenreich, 1911). 
Whilst in the Azores there are nine known species of Peat-mosses, of 
which two are peculiar to the group, there seems to be in each case 
only a single wide-ranging species in Madeira and the Canaries, a 
fact that points to prevailing unfavourable conditions for the develop- 
ment of Sphagnum moors in those islands. 

The Plant-Stocking of the Macaronesian Islands. — But to 
return to our general comparison of the floras of the Macaronesian 
islands, there is a wider outlook of the question, such as Hooker 
presented in his Lecture on Insular Floras (1866), and in his discussion 
of the Canarian flora in his later work on Marocco (1878), and such 



412 PLANTS, SEEDS, AND CURRENTS 



as Christ offered some years after in his contribution to Engler's 
Botanische Jahrbucher (1885). According to Christ, the oldest 
constituents of the Macaronesian floras, such as occur in the Canaries 
and to a less degree in Madeira, are the African plants, as examples 
of which the Cactoid Euphorbias and the Dragon-trees (Draccena 
draco) are amongst the first to attract the stranger's eye, when he 
first visits these islands. Then followed the invasion by Asiatic 
plants, now typefied by genera like Phoebe and Visnea, that are 
identical with or closely allied to genera now existing in the warm 
regions of Asia. Most of the peculiar Canarian genera appear to 
be connected with these early African and Asiatic invasions. 

Since the American elements of the Canarian and Madeiran floras 
seem as a rule to retain their original generic characters, we may 
give third place to the invasion of American plants. They include 
Clethra arborea, a beautiful ericaceous tree, the labiate shrubs of 
Cedronella and Bystropogon, and species of the umbelliferous genus 
Bowlesia, genera that in the aggregate are now most typical of the 
warmer latitudes of South America and of the Andine region. The 
special difficulties concerned with the origin of these American 
elements of the Canarian and Madeiran floras are recognised by both 
Hooker and Christ, and both of them find an explanation in the 
transatlantic carriage of the seeds of the parent plants. Hooker 
writes that " we can but hazard the assumption that at some very 
distant date these genera existed in more eastern parts of South 
America, from whence seeds were transported across the ocean " 
(Marocco, p. 420). Christ appeals at once to the agency of the Gulf 
Stream. However, no evidence of the fitness of these plant genera 
for distribution by currents is produced, and I may say here, having 
had a long experience of the buoyant capacities of seeds and fruits, 
that the future experimenter will most probably find that the agency 
of the currents cannot be invoked. It is possible that the problem 
may assume quite another complexion, seeing that two of the genera 
concerned, Clethra and Cedronella, exist in Eastern Asia, as in Malaya 
and Japan. It may be that the American elements of the Macaronesian 
floras may require the same general explanation that is apparently 
demanded by the almost cosmopolitan connections that linked the 
Canaries and Madeira in the earlier stages of their floral history 
with the warmer regions of the globe. I refer to the original diffusion 
of the same plant-types around the tropics. 

However this may be, the Azores were but little affected by the 
early invasions of Macaronesia by Asiatic, African, and American 
genera. Their floral history begins with the subsequent invasion 
of the same region by South European and Mediterranean genera, 
that now give character to the Laurel woods of the three Macaronesian 
groups. But even this invasion must have taken place at a period 
remote from the present. Although there has been no generic 
dissociation, several of the trees and shrubs are not to be found 
outside Macaronesia, and we should often look in vain in their 
original European home for the parent stocks. Yet, as is shown 
by Hooker and Christ, " the same plants, or their congeners or 
close allies, are found abundantly fossil in the Tertiary strata of 



THE AZORES 



413 



many parts of Europe " (Hooker's Lecture, p. 26). Let me give 
an example, which is typical of much. If there is one tree that is 
characteristic of these Laurel woods of the Macaronesian islands, 
it is Laurus canariensis. Although it is now confined to these islands, 
it grew in South Europe in Upper Tertiary times. It was to this 
and its associated plants that Hooker was alluding when he wrote 
that the vegetation of Europe has undergone a complete revolution 
within the lifetime of species that now so forcibly arrest our attention 
in the forests of the Canaries, Madeira, and the Azores. These 
species, he continues, are living witnesses of that period, when trees, 
now characteristic of Asia and America, formed the forests of the 
European continents. 

The last stage in the history of the indigenous flora of the Macaro- 
nesian islands is that represented by species that still exist in Europe 
and North Africa. It may be said to be still in progress and includes 
the minority of the trees and shrubs of the Laurel woods, and in 
the Azores, in particular, the plants of the upland moors. 

Presumably, therefore, the Canary Islands and Madeira, especially 
the former, hold the wrecks of many floras. To the exclusion of 
the Azores, they possess a number of strange genera and peculiar 
species, that tells us of the ages which preceded the period indicated 
by the non-European trees and shrubs that are common to the 
Laurel woods of all three groups. The waves of African, Asiatic, 
and American plants that have in successive ages passed over this 
portion of the globe, left their wash on the Canarian and Madeiran 
groups before the Azorean islands became available for plant- stocking. 
Whilst the Azores possess no genus of their own, and relatively 
few peculiar species that are beyond suspicion, the Canaries hold 
some ten or twelve genera that are all their own, besides a number 
of genera, of which they share exclusive possession with Madeira. 
It is difficult to separate Madeira from the Canaries in the sense 
that we can detach the Azores ; but the contrasts in the floral history 
of this region may be sufficiently illustrated by the circumstance, 
that, whilst quite one-third of the Canarian species are peculiar, 
the proportion amongst the Azorean plants would not exceed a 
tenth. 

To the student of distribution the Azorean flora offers but few 
"problem" plants; whilst the other two groups, particularly the 
Canarian, present a host of difficulties of this kind. It is possible 
that important episodes in the history of the Azorean flora may have 
their only witnesses in Campanula vidalii and Myrsine africana, of 
which the first is peculiar to the group, while the second is an Asiatic 
and African plant that has been found neither in the Canaries nor 
in Madeira. But it would be idle to speculate on their stories now. 
I would rather close this chapter with the reflection that whilst in 
the Canaries and Madeira quite other questions are often raised 
than those concerned with existing means of dispersal, questions 
that might carry us far back in geological time, with the Azores 
questions dealing with existing modes of dispersal are imminent. 
When Wallace expressed the opinion in his Island Life and in his 
Darwinism that the plant- stocking of the Azores could be attributed 



414 PLANTS, SEEDS, AND CURRENTS 



to existing means of dispersal, he was in the main correct, the great 
mass of the plants being European species. The characteristic plants 
of the Laurel woods, being often peculiar to Macaronesia, do not 
come into this category ; but it will be convenient to deal with their 
dispersal here. To the subject of the agencies of seed-dispersal 
in connection with the Azores, the next chapter will be largely 
devoted. 

Summary 

1. In dealing with the proportion of indigenous Azorean plants, 
it is first pointed out that the native flora was in all probability 
extremely limited. Although it is likely that the total number of 
the alien and native plants would now approach 600, it is held that 
whilst the original flora did not comprise 200 species, the plants 
that gave character to the vegetation did not amount to 100. Multi- 
tudes of plants have been introduced, both intentionally and un- 
intentionally, during the period of almost five centuries that has 
elapsed since the discovery of the group. Stress is laid on the im- 
portance of eliminating the effects of man's agency from every 
flora, and it is observed that such an inquiry would be almost as 
ruthless in its effects on the British flora as it undoubtedly would 
be in the case of the flora of the Azores (pp. 389-91). 

2. The original forests of these islands were composed of ever- 
green shrubs and trees. Among the trees were Tree-Heaths (Erica), 
Laurels (Laurus and Persea), Fayas (Myrica), Hollies (Ilex), Tree- 
Euphorbias, Junipers, Yews (Taxus), species of Rhamnus, Picconia, 
etc. Among the shrubs were species of Daphne, Vaccinium, and 
Viburnum (Laurestinus), and Myrsine africana (p. 391). 

3. The prevailing impression that the original forests were similar 
to the present scrub growth is shown to be an error. There is 
abundant evidence that the islands were heavily timbered when 
first discovered, and that the destruction of the native woods, with 
their large trees, which has been in operation for centuries, has reduced 
the woods to their present condition. The process is still actively 
continued, and it is evident that for generations the visitor has 
formed his impressions of the native trees from " young wood." 
The trees attain a respectable size when preserved; but ages of 
unhindered growth would be required for the development of the 
timber forests that would supply materials, as in the early days, 
for erecting churches and building small ships (pp. 392-8). 

4. The decrease in size of the timber is well illustrated in the case 
of the large size of the original Juniper trees as compared with the 
stunted crooked Junipers of our own times. Amongst the trunks 
of large trees that have been unearthed from the ashes and other 
materials thrown out during the early volcanic eruptions are the 
logs of this Juniper, which must have attained in those times the 
usual large dimensions of the species (J. oxycedrus). As we learn 
from the old writers, the value placed on its timber led to the de- 
struction of this fine tree. Although volcanic eruptions must have 
played their part in the destruction of the original forests, the agency 
of man and animals has been the most effective. As the source of 



THE AZORES 



415 



fuel, land has long been as much valued for the wood that grows upon 
it, as for the food raised from it (pp. 393-5). 

5. The affinities of the native flora are then discussed, and it is 
shown that the characteristic plants of the woods, the moors, the 
ponds and lakes, and the seashore, exhibit a gradually extending 
scale of connections with the outer world, the connections being 
least with the plants of the woods and greatest with those of the 
seashore, the varying degree of isolation thus implied reflecting 
the differences in the history of the dispersing agencies. It is pointed 
out that this principle is of wide application to insular floras, although, 
on account of their lesser antiquity, it has been unable to find its 
full expression in the islands of the Azores. Though geographical 
isolation often counts for much in the differentiation of oceanic 
floras, it is shown that antiquity may largely counteract the effects 
of contiguity to a continent. The example is taken of the Canaries, 
a group probably far more ancient than that of the Azores. Although 
only some fifty miles from the nearest mainland as compared with 
800 miles in the case of the Azores, the Canaries hold a flora that 
is far more differentiated, the proportion of peculiar species being 
at least three times as great (pp. 398-400). 

6. After tabulating the distribution of the characteristic plants 
of the Azores according to their station, the writer shows how they 
illustrate the progressive widening of the connections with the outer 
world. With the plants of the woods the most conspicuous features 
are these. Whilst mainly non-European, they are largely Canarian 
and Madeiran, that is to say, Macaronesian. On the other hand, 
the affinities of the plants of the upland moors and of those of the 
ponds and lakes are very markedly European, there being no American 
connection that is not also European. In the case of the plants 
of the seashore, though predominantly European, we get the first 
indications of independent and direct connections with the American 
side of the Atlantic. Though the affinities of the flora are pre- 
eminently European, a possible derivation of European plants by 
the way of the mountains of North-west Africa is suggested in some 
cases (pp. 400-407). 

7. The author then contrasts the zones of vegetation on the great 
cone of Pico as representing the Azores, on the Peak of Teneriffe 
as representative of the Canaries, and on Madeira. After describing 
those of Teneriffe, he discusses the differences that we ought to 
expect in the cases of Madeira and the Azores from the differences 
in latitude and the associated differences in climate. It is then 
inferred that the extensive lower zone (the African zone) of Teneriffe 
would be much restricted in Madeira, and absent altogether in the 
Azores, whilst the Laurel woods, which have many features in common 
in all three groups and lie from 2000 to 2500 feet above the sea 
on Teneriffe, would descend to about 1000 feet above the sea in 
Madeira, and, when permitted by the cultivator, would descend to 
the coast in the Azores. All these predictions are then shown to 
be substantially realised, but the reader is referred to the text for 
the particulars (pp. 407-10). 

8. It is also brought out in this comparison that the Junipers 



416 PLANTS, SEEDS, AND CURRENTS 



of the upper woods of Pico, which descend to about 2000 feet above 
the sea, were originally well represented in the higher levels of Madeira 
(probably above 3000 feet), and also on Teneriffe, at elevations 
of 5000 to 7000 feet, where they corresponded in their vertical range 
with the belt of Finns canariensis, the pines being unrepresented 
either in Madeira or in the Azores (pp. 409-10). 

9. A comparison is then made of the summit plants of Pico, 
Madeira, and Teneriffe, and it is shown that they have little in common, 
those of Pico being derived from the moors below, these upland 
moors with their plants being in a general sense unrepresented on 
either Madeira or Teneriffe (p. 411). 

10. The chapter then closes with a short comparison of the histories 
of the plant-stocking of the three Macaronesian groups. Whilst 
with the Canaries, and to a less extent with Madeira, there were 
early invasions of African, American, and Asiatic plants, they made 
but little mark on the Azores. The Azorean flora appears not to 
have shared in such revolutionary changes, and its history begins 
with the later invasion in Upper Tertiary times from Southern Europe 
and the Mediterranean region of plants that in their descendants 
now give character to the Laurel woods of all three Macaronesian 
groups. The parent stocks have since been driven from their 
European home, and the Laurel woods of Macaronesia are all that 
remains of a period when trees now characteristic of Asia and America 
formed the forests of our continent (Hooker). The last invasion 
of Macaronesia, which has extended down to recent times, is indi- 
cated by those plants that still exist in South Europe and North 
Africa. It is represented by the minority of the plants of the 
woods, and particularly in the Azores by the plants of the moors 
(pp. 411-13). 

11. In the case of the Canarian flora, which is made up of the wrecks 
of many floras, questions quite other than those concerned with 
existing means of dispersal are mainly raised. With the Azorean 
flora, however, which has shared only in the later revolutionary 
changes of the plant world in this region, the means of dispersal 
will figure prominently in any inquiry into its history; and to this 
subject the next chapter is largely devoted (pp. 413-14). 



CHAPTER XIX 



the azores (continued) 

The Relation between the Differentiating Influences and the Dispersing 
Agencies. — Before referring to the modes of dispersal of the plants 
of different stations, I will briefly indicate how we may interpret 
the relation between the differentiating influences and the dispersing 
agencies. Though the specific divergence of most of the plants 
of the woods of the Azorean islands indicates a breaking of the link 
established by frugivorous birds with their European home, there 
is an important minority, as before remarked, made up of plants 
specifically identical with those of Europe, which testify that a 
connection has sometimes been maintained down to recent times „ 
The majority include plants of the genera Hedera, Ilex, Laurus T 
Myrica, Rhamnus, Smilax, Vaccinium, etc., and the minority com- 
prise species of Daphne, Juniperus, Viburnum, etc. But even with 
the minority there are signs of the rupture of the connection with 
the continent. Thus Juniperus oxycedrus has developed an Azorean 
variety (var. brevifolia) which has puzzled the botanist, and Viburnum 
tinus has developed an Azorean form (var. subcordata) which according 
to Trelease seems to be nearer to a Canarian species than to the 
parent species of the neighbouring continent. Looking at these 
facts we may regard the connection between the plants of the woods; 
of the Azores and those of Europe as either broken or breaking. 
But the connection has been kept up with Madeira and the Canaries, 
and it would seem that in recent times the activities of frugivorous 
birds as dispersing agents have been mainly restricted to the Macaro- 
nesian region. It is very different, however, with the plants of the 
mountain moors and with the aquatic and subaquatic plants, where 
the community with European species leads one to infer that the 
connection by birds has been usually continued down to recent times. 

The Modes of Dispersal of the Plants of the Azores. — Generally 
speaking, the prevailing shrubs, trees, and climbers of the woods are 
known to be dispersed, or are regarded as likely to be dispersed, by 
frugivorous birds, such as those of the genera Daphne, Hedera, Ilex, 
Juniperus, Laurus, Myrica, Rhamnus, Smilax, Taxus, etc.; whilst 
the plants of the dry and wet upland moors of the genera Anagallis, 
Calluna, Carex, Hydrocotyle, Menziesia, Polygala, Potentilla, Thymus, 
etc., as well as those of the waters and of the borders of ponds of 
the genera Callitriche, Littorella, Peplis, Potamogeton, Scirpus, etc. 3 . 
possess small and often minute seeds or seed-like fruits, for the 
dispersal of which we must look to birds of other habits. The seeds 
E E 417 



418 PLANTS, SEEDS, AND CURRENTS 



of plants of the shores would be distributed directly by currents, 
as with Critkmum and Ipomcea, or indirectly in the crevices of drifting 
logs, as with the small-seeded Silene and Spergularia, or by sea- 
birds through adhering to their feet and legs, as with Plantago and 
tJuncus, or carried in their stomachs, as with Polygonum. Very 
few of the truly native plants of the Azores are fitted for attachment 
by hooks or similar appendages to birds, the Azorean Sanicula 
standing very much alone in this respect. It is a genus that has 
found its way in this manner to several oceanic islands besides the 
Azores, such as Madeira, the Canary Islands, Juan Fernandez, 
Hawaii, etc. The number of small- seeded flowering plants that 
must be lumped together under the head of those distributed in 
mud adhering to birds is large. This " limbo " of the student of 
dispersal, to which he assigns a multitude of plants, is not altogether 
satisfactory; but for the oceanic island we are left but little choice, 
since only the spores of cryptogams, as is shown below, are adapted 
for transport by winds over broad tracts of ocean, and not even the 
minute seeds of J uncus or the yet smaller seeds of Orchids could 
avail themselves of this agency. We come now to deal more in 
detail with the modes of dispersal of Azorean plants according to 
their stations, and will begin with those of the woods. 

1. The Modes of Dispersal of the Plants of the Woods. — As already 
observed, most of them would be dispersed by frugivorous birds, 
such as pigeons. The specific or varietal differentiation of the 
majority of them within the Macaronesian region indicates, as we 
have seen, a breaking of the link with their original European home ; 
and it is remarkable that this divergence corresponds with sub- 
specific differentiation in the Macaronesian islands of the European 
wood-pigeon, Columba palumbus, whilst the rock-pigeon, Columba 
livia, has developed an Azorean variety (Hartert and Ogil vie- Grant, 
Godman). The Canarian wood-pigeons, as we learn from Lord 
Lilford's book on birds (1893, p. 70), and the Azorean pigeons, 
according to Drouet, feed largely on the fruits of Persea (Laurus) 
indica. Pigeons are credited with a liking for the fruits of other 
genera of plants found in the woods of the Azores, such as Ilex and 
Hedera. Doubtless the pigeons of Macaronesia are also partial 
to the fruits of Myrica faya, the hard stones of which would be 
probably ejected unharmed. The other genera of the woods, such 
*as Daphne, Juniperus, Picconia, Rhamnus, S mil-ax, Taxus, Vaccinium, 
Viburnum, etc., would be distributed by frugivorous birds. It 
.may be added that stragglers may have played an important part 
in this process, and that we are not restricted in this respect to birds 
.that regularly visit the islands. In this manner the missel-thrush 
;may have introduced the first seeds of the Yew (Taxus baccata) into 
the group, a matter dealt with in the remarks on that plant in a 
later page of this chapter. 

2. The Modes of Dispersal of the Plants of the Upland Moors. — - 
Though we have here again to appeal to the bird, the indications 
are often largely conjectural. The plants concerned have for the 
most part either dry small seed-like fruits or minute seeds. The 
following is a series of measurements of some of the seeds stater 



THE AZORES 



419 



in the order of their size — Juncus, 0-33 mm.; Calluna vulgaris, 
Menziesia polifolia, Sibthorpia europcea, all 0-5 mm. ; Thymus serpyllum 

0- 66 mm.; Anagallis tenella, 0-75 mm.; Lysimachia nemorum, 1-0- 

1- 3 mm. ; Luzula, 1-3 mm. ; Potentilla tormentilla, 1*8 mm. 

The seeds of Juncus were found by Darwin and others in dried 
mud adhering to birds. (I do not find many references to Juncus 
in my notes, but species such as bufonius, effusus, capitatus, etc., 
are characteristic of the Azorean flora.) Probably the seeds of plants, 
like Anagallis tenella, that grow in boggy ground would be transported 
in the same way. But one could scarcely appeal to such an agency 
in the case of plants of dry moors, such as Calluna vulgaris and Men- 
ziesia polifolia. Yet many birds frequent such moors, even gulls 
and curlews in certain seasons, and it is possible that the minute 
seeds of Calluna might become entangled in their plumage, when, 
as often happens, they make their nests of heather. 

Except with Luzula and Juncus, the seeds of but few of the Azorean 
moor plants would, according to my observations, emit mucus 
when placed in water, or become slimy when moistened, a property 
that enables seeds to adhere firmly to plumage on drying. But the 
quality is a variable one, even with the same species, as is indicated 
by their behaviour in my later experiments in England on the seeds 
of Luzula campestris, L. pilosa, and L. sylvatica, and of species of 
Juncus, a subject also dealt with in my previous work on the Pacific 
Islands (p. 567). It is highly probable that a bird brushing past 
such plants in wet weather would carry off on its feathers a number 
of the wet seeds of Luzula and J uncus, and that they would adhere 
firmly to its plumage when dry. The cause of this tendency to 
become slimy and sticky when wetted is described by Buchenau 
in the cases of the seeds of Luzula and Juncus in his monograph on 
the Juncacece (Pflanzenreich, 1906, pp. 25, 30). It is well exhibited, 
he says, in the case of a species of Luzula peculiar to the Canary 
Islands. At least five of the nine European species of Juncus 
found in the Azores display this property in their seeds, and several 
of the species most widely distributed over the world are known to 
exhibit it. The aid thus given to dispersal in the case of plants 
of many different genera was emphasised in my book on Plant 
Dispersal (p. 567) ; but it had long before been recognised by Kerner 
and others, and Buchenau also lays stress on the part which animals 
would thus play in the distribution of species of Luzula and Juncus. 
As they brush past the plants in wet autumn weather they would 
carry away either on their fur or on their plumage the sticky seeds 
from the open capsules. 

Yet we are in the case of these small-seeded plants often brought 
into contact with problems that raise other questions than those of 
modes of dispersal. Let us take the three plants with seeds half 
a millimetre in size, Calluna vulgaris, Menziesia polifolia, and 
Sibthorpia europ&a. Calluna has a solitary species which is mainly 
European, though it has obtained a hold on the Atlantic side of North 
America. Menziesia has half a dozen species found in Europe, 
4sia, and North America, but although one at least is common to 
he eastern and western hemispheres, M. polifolia is confined to 



420 



PLANTS, SEEDS, AND CURRENTS 



Western Europe and the Azores. Sibthorpia holds a similar number 
of species which live in the Andes, in the mountains of Mexico, in 
Europe, in Africa, and in Nepaul. The Canary group has its own 
species, and Sibthorpia europcea not only extends to the Azores, 
but is found in the mountains of the Cameroons and in the Abyssinian 
Alps. 

3. The Modes of Dispersal of the Aquatic and Subaquatic Plants. — 
It may be observed that in most cases these Azorean plants possess 
minute seeds or very small seed-like fruits, such as we find in Peplis 
portula, Littorella lacustris, Callitriche aquatica, and Scirpus fluitans, 
which could have been transported to the group in mud adhering 
to birds. The small fruits of the common Potamogeton (P. poly- 
gonifolius) are 2-3 mm. in size and float in quantities on the surface 
of the ponds and lakes in the latter part of the summer. They 
would be readily swallowed by wild ducks and other waterfowl, 
and I have shown in my book on Plant Dispersal (pp. 369, 513), not 
only that the fruits of Potamogetons are to be found in the stomachs 
of these birds, but that they germinate much more readily after 
passing through a bird's digestive canal. This Potamogeton figures 
on the island of Pico as an aggressive species that is gradually taking 
possession of the mountain lakes and ponds and is ousting such 
plants as Littorella lacustris and Isoetes lacustris (I. azorica, D.) 
from the shallows. Doubtless it is a more recent arrival than the 
two species just mentioned. As to the spores of Isoetes it may be 
remarked that they were most probably brought in dried mud adhering 
to the feet of birds of aquatic habits. The seed-like fruits of the 
cyperaceous species that line the water's edge, Car ex flava, Scirpus 
multicaulis, S. palustris, etc., were, it is likely, originally transported 
in the stomachs of waterfowl. Wild ducks, as has been shown 
in the work above quoted (p. 513), swallow the hard nutlets of 
Cyperacece in quantities, and these fruits readily germinate after 
being removed from the stomach and intestines. The fruits of 
Scirpus palustris sink, but those of Carex flava buoyed up by the 
utricle float for six months and more, and form a constituent of the 
floating drift of ponds. 

4. The Modes of Dispersal of the Coast Plants. — The littoral flora 
of the Azores is scanty owing to the coast being usually rock-bound. 
We might have expected as in tropical regions that the currents 
would have been important agents in stocking these shores with 
their plants, but, unless we include the intermediate agency of the 
drifting log, they have not taken a prominent part. In this respect 
the littoral flora of the Azores behaves like the shore floras of temper- 
ate latitudes (see Plant Dispersal, p. 33). The following are the 
results of the writer's observations on the capacity of the seeds or 
fruits for direct transport by currents. 

When the data are supplied by old experiments and observations 
to be found recorded in the writer's previous book on Plant Dispersal 
they are marked O. 

Beta maritima. — The nutlets sink in sea-water, but enclosed in 
the perianth, whether fresh or dry, they may float for two or three 
days (O). 



THE AZORES 



421 



Cakile edentula. — The upper joints of the fruits float for nine 
or ten days. Probably introduced in ballast from America (see p. 189). 

Crithmum maritimum. — The original flotation experiments in 
sea-water covered ten months, 95 per cent, of the carpels remaining 
afloat (O). They were subsequently extended to thirteen months, 
when 90 per cent, remained afloat, a few of which germinated in 
soil two months later. 

Euphorbia azorica. — The seeds float in sea-water from one to two 
weeks, but the water soon penetrates their coats. In the case 
of E. peplis he has no data; but the floating powers are probably 
limited. 

Hyoscyamus albus. — The seeds sink. 

Ipomcea carnosa. — The seeds float unharmed in sea- water for twelve 
months and more and germinate afterwards (see p. 218). 
J uncus acutus. — The seeds sink. 
Plantago coronopus. — The seeds sink. 

Polygonum maritimum. — The nutlets sink in sea- water, but en- 
closed in the perianth they float three or four days. The entire 
plant, or branches of it, would float five or six days when carried off 
a beach by the waves (O). 

Salsola kali. — Enclosed in the perianth the fruit floats in sea- water 
for a few days, but when detached it sinks. Portions of the plant 
bearing mature fruits float at first, but sink within ten days (O). 

Samolus voter andi. — The seeds sink (O). 

Silene maritima. — Seeds sink (O). 

Solidago sempervirens. — No data, but prolonged buoyancy is 
unlikely. 

Spergalaria marina. — Seeds sink (O). 

Of the fifteen shore plants above named only two, Crithmum 
maritimum and Ipomcea carnosa, can be regarded as adapted for 
transport by currents to the Azores. Nearly half of them have 
small seeds, namely, the species of Hyoscyamus, J uncus, Plantago, 
Samolus, Silene, and Spergularia. It is not unlikely that the seeds 
of the Hyoscyamus, Silene, and Spergularia, are carried in the crevices 
of drifting logs. But sea-birds are also able to assist in the distri- 
bution of these small seeds. Gulls, for instance, often make their 
nests on the faces of cliffs in the midst of a dense growth of Sea- 
Campion {Silene maritima) ; and it would be surprising if they did 
not aid in the distribution of this plant. Still more likely would 
this be with Plantago coronopus, which grows on the rock-ledges 
where these sea-birds nest. Here the seeds emit mucus and become 
sticky when wetted, and they would adhere firmly to a bird's plu- 
mage when dry. The small seeds of Samolus valerandi have been 
found in mud adherent to birds; and the frequent growth of the 
plant in wet places by the sea would afford opportunities of this 
occurring (Kerner). The prickly pointed leaves of Salsola kali would 
enable bits of the plant carrying fruits to catch in feathers as readily 
as they do in one's clothes. Many granivorous birds are fond of 
Polygonum nutlets, which are often found entire in their stomachs ; 
and doubtless birds frequenting beaches would swallow the seeds 



422 PLANTS, SEEDS, AND CURRENTS 



of Polygonum maritimum. The seeds of J uncus acutus, like those 
of other species of the genus referred to on a previous page, would 
probably become sticky when wet, and would thus adhere firmly 
to a bird's plumage. 

The Efficacy of the Wind in the Oversea Dispersal of Seeds. — Much 
has been written, but few actual facts have been recorded relating 
to this subject. Mr. Wallace in his Darwinism (1889) made a 
strenuous appeal for the paramount influence of winds over birds 
in transporting small seeds like those of Sagina and Orchis over tracts 
of ocean 1000 miles in width. " For each single seed carried away 
by external attachment to the feet or feathers of a bird, countless 
millions (he says) are probably carried away by violent winds ; and 
the chance of conveyance to a great distance and in a definite direction 
must be many times greater by the latter mode than by the former " 
(p. 373). He based his opinion upon the careful comparison of the 
size of a number of small seeds with those of quartz grains, 2^o^ n °^ 
an inch across, found in deep-sea deposits 700 miles from land and 
regarded by Sir John Murray as distributed by the winds. 

There seems to be no question about the fitness of cryptogamic 
spores for dispersion by winds across broad tracts of sea. It is 
concerning the seeds of flowering plants that doubts would be raised. 
The great contrast in weight between the lightest of small seeds, as 
in those of orchids, and the average weight of a mushroom spore 
(orchids, 8000-15,000 seeds to a grain, Wallace and Kerner; mush- 
room spores, probably some hundreds of thousands to a grain) at 
once indicates problems of a very different nature. With regard 
to species of flowering plants represented in the Azores, the following 
measurements of size and weight were obtained by the author with 
the exception of those for Sagina procumbens which are supplied by 
Wallace in the work above named. 



Sagina procumbens, of an inch, 12 ^ 00 of a grain. 
J uncus communis, 
Erica azorica, 
Calluna vulgaris, 
Sibthorpia europaza, 
Menziesia polifolia, 
Thymus serpyllum, 
Lysimachia nemorum, 
Cotyledon umbilicus, 



i 

7 5 
1 

55 
1 

517 

1 
5^0 

1 

7T0 
1 

40 

>,A 

1 

T5 



1 

5500 

2T00 
1 

2000 
1 



Note. — The relation between size and weight varies with the form 
of the seed. Thus the rounded seeds of Thymus are much heavier 
for their size than the oblong somewhat flattened seeds of Calluna. 



Yet minute as the seeds of many widely distributed flowering 
plants may be, Wallace gave no weight to a very important factor 
in the continuous action of gravity, which seems to nullify any fitness 
such seeds might appear to possess for transport by the winds across 
a broad tract of ocean. All that follows, relating to this factor, 
is based either directly or indirectly on materials supplied by Mr. 



THE AZORES 



423 



Lloyd Praeger in his botanical memoir published in the reports of 
the Clare Island Survey in 1911 (Proc. Roy. Irish Acad.). The appli- 
cation of his data to the Azorean flora is my own, and possibly the 
author may pardon me for making such a free use of his work ; but 
it will best express the measure of my indebtedness. 

The contrast in weight between the smallest seeds of flowering 
plants and the spores of cryptogams, reflects the difference between 
inefficient and efficient dispersal by winds over great distances. 
Mere reduction in size, writes Lloyd Praeger (p. 79), is not carried 
far enough in the flowering plants to produce efficient dispersal by 
winds. With their seeds we can detect a certain amount of relation 
in their responses to the action of gravity between their size and 
falling rates ; but quite another order of things presents itself in the 
case of cryptogamic spores. Small and light as it is, the seed of an 
orchid falls through the air at least fifty times as fast as the spore 
of an ordinary mushroom. Here I have taken the average terminal 
velocity of an orchid seed at one foot per second and of a mushroom 
spore at 6 mm. a second. It will be seen below that according 
to the data given in Prof. Buller's British Association paper (1909, 
p. 675) the average falling rate for hymenomycetous spores would 
probably be much less; but in order not to overstate the contrast 
the most rapid rate has been chosen. This comparison will serve 
to illustrate the remark in Lloyd Praeger' s paper (p. 70) that the 
behaviour of small particles falling in air differs from that of larger 
bodies, inasmuch as with continual reduction in size the impelling 
force of gravity becomes rapidly smaller in comparison with the 
decrease of resistance offered by the air, so that very small velocities 
result. 

At the close of Chapter XVI. this matter is briefly mentioned in 
connection with the Peat-mosses. Here it is treated more at length 
with reference to the Azorean flora. It would appear from the 
numerous experiments of Lloyd Praeger on the falling rate of seeds, 
using the term " seed " in a general sense as implying in the words 
of this writer the unit of dispersal, that except in the case of plumed 
seeds of the lightest weights, such as those of Typha and Epilobium, 
we could not appeal to the winds for the transport of even the smallest 
seeds of flowering plants, this agency being only available for the 
spores of cryptogams. 

To postulate the effects of gravity, as indicated by the falling 
rate of seeds and spores, an initial altitude at the starting-place must 
be assumed. If the wind has been effective in stocking the Azores 
with plants we must regard Southern Europe as the starting-place, 
since that is the source of the great majority of the small- seeded 
flowering plants. Taking the distance of this group from the nearest 
coasts of Portugal at about 800 miles, I have below given the minimum 
initial elevation that would be required for seeds and spores to reach 
the Azores with a favourable wind blowing with the force of a strong 
gale at fifty miles an hour. The falling rates of the spores are taken 
from some of the results obtained by Prof. Zeleny and Mr. 
McKeehan, as well as by Prof. Buffer, which are given in the 
British Association Report for 1909 (pp. 408, 675) and in Nature 



424 PLANTS, SEEDS, AND CURRENTS 



for October 14, 1909, those for the seeds being supplied by Mr. 
Lloyd Praeger's report in the Clare Island Survey (Proc. Roy. Irish 
Acad., XXXI., 1911). All the plants indicated under the various 
headings are with the exception of Typha latifolia represented in 
the present flora of the Azores. 

Table illustrating the Falling Rates op Spores and Seeds and the Initial 
Elevation that they would require if transported by the Wind from 
the Uplands op Portugal to the Azores, a Distance op about 800 Miles. 
(See above por explanatory remarks.) 





Falling Rate. 


Minimum Initial Elevation with 
favourable wind blowing fifty 
miles an hour. (Elevations 
approximate.) 


Hymenomycetes (mush- 
rooms in a general 
sense). 


- 3 to 6 mm. per second 
(B-). 


oi to iiou ieet. 


Lycoperdon (puff-ball). 


- 46 mm. per second 
(Z. and M.). 


86 feet. 


Polytrichum. 


2-28 mm. per second 
(Z. and M.). 


430 feet. 


Lycopodium. 


17 '7 mm. per second 
(Z. and M.). 


3300 feet. 


Typha latifolia (plumed 
seed). 


12 feet in 34 seconds. 


20,000 feet or 3i miles. 


Epilobium (plumed seed). 


12 feet in 20 seconds. 


35,000 feet or 5| miles. 


Sonchus oleraceus, 
Senecio vulgaris 
(both plumed seeds). 


12 feet in 12-7 and 12-8 
seconds. 


54,000 feet or nearly 9 
miles. 


Habenaria (orchid). 


12 feet in 12 seconds. 


58,000 feet or 9J miles. 


Carduus pycnocephalus 
(plumed seed). 


12 feet in 5 seconds. 


138,000 feet or 22J miles. 


Sagina procumbens. 


12 feet in 3-5 seconds. 


197,000 feet or 32 miles. 


Juncus. 


12 feet in 3 seconds. 


230,000 feet or 38 miles. 



We may infer from the data just given, assuming that the argument 
is valid, that whilst there would be no difficulty in postulating the 
requisite initial uplift for cryptogamic spores we could not do so 
for the seeds of J uncus and Sagina procumbens, however small they 
may be. But the difficulty is not so great as it at first seems for those 
seeds that require an initial elevation of from six to ten miles, as 
in the case of Epilobium, Senecio, Sonchus, and Habenaria, Typha 
being excluded as it is not found in the Azores. If the wind blew 
with the extreme maximum force of a hurricane, say, at 100 miles 
an hour, the lift requisite for the seeds would be halved and the 
passage to the islands would be accomplished in eight hours. Under 



THE AZORES 



425 



such conditions Epilobium would only require an initial elevation 
of about 17,500 feet. Senecio vulgaris and Sonchus oleraceus would 
require about 27,000 feet, and Habenaria about 29,000 feet. I am 
not assuming that any of these flowering plants were introduced 
into the Azores by the winds. In fact, there is good reason for 
holding that in the case of the plants with plumed seeds they were 
introduced as weeds. But it is quite possible that Epilobium seeds 
might be carried across a tract of ocean, a few hundred miles broad, 
if they began the passage high up a mountain's side. 

The up-draught that occurs on the slopes of lofty mountains 
would soon carry the spores of cryptogams to levels several thousands 
of feet above the sea. These ascending currents, according to 
Whymper, Humboldt, and others, transport insects up to levels 
of from 15,000 to 19,000 feet on the Andes, and, as the writer himself 
observed, to the summit of Mauna Loa in Hawaii, about 13,600 feet 
above the sea {Plant Dispersal, p. 585). As discussed in the work 
just quoted, they form an important factor in the climatic regime 
of mountain regions, and as such they are treated by Samler Brown 
in the case of the Peak of Teneriffe in his Guide to the Canary Islands 
(1905, pp. e24-e29). 

The most pertinent example of oversea transport of seeds by the 
winds that can be quoted in this connection is that given by Warming 
in his writings on Greenland and the Faroe Islands, and referred to 
by Sernander in his work on Scandinavian vegetation. Here large 
quantities of plant debris, mostly fruits of Calluna vulgaris mixed 
with blossoms of Erica tetralix, were, during a gale in February 1881, 
blown across the Cattegat from the Swedish coast to the eastern 
shores of Jutland, a distance of 110-120 kilometres. But if we wish 
to believe that the islands of the Azores were originally stocked with 
Calluna vulgaris in this manner, we are concerned with transport 
over a tract of ocean thirteen times as broad as the Cattegat. It 
is not possible to deal further with these matters here, and the reader 
may be referred for a general discussion of the subject of the wind 
as a transporting agency to Lloyd Praeger's pages and to Ernst's 
New Flora of Krakatau. 

Notes on the Plants of the Azores 

These notes may be prefaced with the remark that there is in 
general a close agreement between the ranges of the altitudes obtained 
by myself on Pico and those ascertained for the same mountain by 
Hochstetter, with whose work I was at that time quite unacquainted. 
Watson (p. 114) writes in a depreciatory tone of the 44 alleged ranges 
of altitudes " given in Seubert's Flora, and ignores them altogether. 
They were all derived from Hochstetter, and are in my opinion 
generally to be relied on. They are often given in the following 
notes, some of them being taken from the paper by Seubert and 
Hochstetter in Wiegmann's Archiv. 

Acrostichum squamosum, Sw. — Grows on Pico at altitudes of 2000 
to 5000 feet. Hochstetter, 2500 to 5000 feet. 

Anagallis tenella, L. — It is singular that a plant so abundant 



426 PLANTS, SEEDS, AND CURRENTS 



in the wet moors of the uplands of the island of Pico, should, as far 
as its previous identification by Drouet is concerned, have been 
regarded with a little suspicion by Watson (p. 213). With Arceutho- 
bium oxycedri and Hydrocotyle vulgaris it escaped the notice of the 
Hochstetters. Drouet recorded it from Pico and Santa Maria. 
Trelease found it on Flores, and it can scarcely be doubted that it 
will prove to be abundant on San Jorge. It flowers abundantly 
in July, and grows at altitudes of 2000 to 4000 feet. The results of 
my observations on a peculiar habit of growth of the plant in England 
are given in Note 24 of the Appendix. 

Arceuthobium oxycedri, M.B. — The name of this genus is a compound 
of two Greek words, and signifies " living on the Juniper," Juniperus 
oxycedrus serving as the host for this parasite in South Europe. 
The writer was the first to record this plant from the Azores. It 
first came under his notice in March 1913, growing plentifully upon 
the trunks and branches of the Junipers (J. oxycedrus, var. brevifolia) 
on the Bandeiras or north-west slopes of the great mountain of Pico 
at altitudes of 2500 to 2800 feet, its brownish-yellow or gamboge hue 
making it a striking object on the dark-coloured trees. During this 
season it did not come under my notice on the southern slopes of 
the mountain ; and had it not been for a chance ascent above Ban- 
deiras I should have left Pico, like the Hochstetters, without being 
aware of its existence. On sending the specimens to Kew, the 
Assistant-Director, Mr. A. W. Hill, wrote to me saying : " We are very 
interested in your discovery on the slopes of Pico. The parasite 
proves to be Arceuthobium oxycedri, M. Bieb. We have no specimen 
of this from the Azores, nor can we find any record of its having 
been found there previously." In the summer of the following year 
I came upon it growing frequently on the Junipers at elevations 
of 3000 to 4000 feet on the south-east and east slopes of the mountain. 
It also came under my notice off the mountain, growing on the 
Junipers in the vicinity of the Lagoa das Teixas which is situated 
at an altitude of 2500 feet at the back of San Roque. Here its growth 
was more luxuriant than on the cone. 

The species has a wide distribution in South Europe, and, as in 
the Index Kewensis, is generally credited also to North America ; 
but Mr. Hemsley in a letter to me writes that it would be worth while 
looking into the question of the specific identity of the North American 
plant commonly referred to Oxycedri. Ten species are enumerated 
in the Index Kewensis, of which eight are confined to North America 
and one to the Himalayas, whilst the species under consideration 
is the only one common to Europe and North America. Sir D. 
Brandis in his Indian Trees states that A. oxycedri grows in the Hima- 
layan region on Juniperus macropoda at elevations of 9000 to 11,000 
feet. According to Arcangeli's Flora Italiana, Arceuthobium 
oxycedri ranges in South Europe from Spain to Servia, and occurs 
also in North Africa, the Taurus, and Persia. Harshberger, in his 
work on the Phytogeography of North America (pp. 555, 556, 608), 
mentions three species, all growing on Pines, one in the Southern 
Rocky Mountains at elevations of 8000 to 10,500 feet, and the two 
others in the Colorado and Californian regions. Urban (VII., 205) 



THE AZORES 



427 



describes a new species from an altitude of 4000 feet in the mountains 
of San Domingo in the West Indies. 

The mode of dispersal of the genus Arceuthobium is illustrated in 
the cases of A. oxycedri and A. occidental as described bv T. Johnson 
and G. J. Peirce in the Annals of Botany (Vols. II. 1888, XIX. 1905). 
The seeds are discharged " explosively,' 5 and are about a millimetre 
in size. Their flight may cover a distance of fifteen to twenty feet, 
and on account of their viscid exterior they adhere firmly to sub- 
stances, the attachment holding for many months or even for a 
year. It is thus likely that birds actively disseminate the species, 
carrying the seeds firmly adhering to their plumage. In this respect 
Arceuthobium resembles Luzula, which is mentioned in this connection 
in an earlier page of this chapter, and it is noteworthy that the two 
genera have a similar distribution. 

Cakile edentula, Big. — See p. 384. 

C allium vulgaris, S. — Begins to flower at the end of July. Grows 
at all elevations on Pico from the coast to the top of the peak. 

Campanula vidalii, W. — This plant is peculiar to the Azores. It 
was first gathered by Captain Vidal in 1842 from " an insulated 
rock " off the coast of Flores. Watson subsequently made an un- 
successful search for it on the main island (p. 188). Afterwards 
(1844-48) Mr. Carew Hunt found it " very locally on the coasts of 
San Miguel and Santa Maria," and it was from one of these islands 
that it was introduced into English gardens (Ibid.). It is one of 
the most beautiful plants of the Azores, is stout and shrub-like, 
attains a height of two feet, and has milk-white flowers, one to one- 
and-a-half inches long, the corolla being constricted in the middle. 
Trelease, who visited the group in 1894 and 1896, speaks of it as then 
occurring " on cliffs and detritus by the seashore and on outlying 
rocks around the entire island of Flores " (p. 128). He alludes to 
the impression in the islands that it occurs in cultivation only outside 
Flores and was originally derived from that island. However, in 
1909 Druce found it on the cliff-side at Capellas on the north-west 
coast of San Miguel (Journal of Botany, 1911), and the present writer 
came upon it there on the same cliff-side in 1913. As regards its 
habitats in the group, it should be borne in mind that when it was 
first collected by Captain Vidal amd Mr. Carew Hunt, 1842-48, the 
islands of San Miguel and Santa Maria were as much entitled as that 
of Flores to be considered the proper habitats of the species, since 
in all three cases the indications went to show that it was a scarce 
coast plant. Where observed by Mr. Druce and myself on the cliffs 
of San Miguel it was growing in its natural station. Both Dr. 
Carreiro and himself regarded it as truly indigenous in that locality. 
It did not come under my notice on Pico, but it may grow on San 
Jorge, and I am inclined to consider that it was originally widely 
distributed over the Azores and is on the road to extermination. 
It seeds profusely and germination takes place readily as the 
seeds lie on the soil. Like Watson, I raised plants in my garden 
from Azores seeds ; but on the coast of South Devon they are much 
injured by the severer frosts when kept out of doors "during the 
winter, but few surviving. 



428 PLANTS, SEEDS, AND CURRENTS 



Questions of modes of dispersal seem hardly pertinent in the case 
of a plant that like this species is restricted to a single group of 
islands. The seeds are smooth, 0-75 mm. long, and they sink in 
sea-water. They appear as well fitted for wide dispersal as those 
of a multitude of small- seeded plants with great ranges. The history 
of this species probably carries us back to an early stage in the plant- 
stocking of the Azores. Watson writes (p. 189) that each group of 
Atlantic islands (Azores, Madeira, Canaries, Cape Verdes) has its 
peculiar Campanula, the Madeiran and Canarian plants affording 
technical characters for generic distinction, whilst that of the Azores 
is " a true Campanula, though with the habit of a shrubby Semper- 
vivum." A clue to the parentage of the Azorean species may perhaps 
be found in the form of the first leaves. Whilst the typical leaves 
are long, lanceolate-spathulate, and serrate, the cotyledons are entire, 
broad, and almost deltoid. The first leaf is similarly broad, 
but subcordate at the base, and fringed with long hyaline 
hairs. The serrations begin to develop in the second leaf, which 
is ovate in form. The transparent hairs disappear after the fourth 
leaf, which is broadly oval and deeply notched. The succeeding 
leaves rapidly assume the characteristic lanceolate-spathulate form 
which is acquired in the sixth or seventh leaf. 

Daphne laureola, L. — The " Trovisco " of the Azoreans. Only 
recorded from Pico. Though Seubert, whose notes were supplied 
by the Hochstetters (1838), mentions no other island, Drouet who 
visited the group in 1857 was assured that there was formerly much 
of it in the valley of Furnas, San Miguel. It is highly probable 
that it grows on San Jorge. I found it in flower-bud in the end of 
March and beginning of April 1913, and in early green fruit in the 
first half of July 1914. Evidently it flowers in May. Grows on 
Pico at levels between 3000 and 5000 feet. According to Hochstetter 
it is found at elevations of 3000 to 4000 feet. Watson observed it 
" probably between 4000 and 5000 feet " (Lond. Journ. Bot, 1843). 

Dicksonia culcita, Herit. — On Pico it grows at altitudes of 2000 
to 4500 feet. Hochstetter places it in the zone of the upper mountain 
woods, 2500 to 4500 feet. In San Miguel it reaches the tops of two of 
the principal mountains, Pico da Vara, 3570 feet, the highest peak 
in the island, and Agua de Pao, 3070 feet. 

Erica azorica, Hochst. — Flowers in May and June. When men 
or cattle brush against the branches in June dense clouds of pollen 
are given off. Fruits in July and August. Ranges in altitude on 
Pico from the coast to 6000 feet, but it is much dwarfed in the higher 
levels, namely, above 4500 feet. Seubert, quoting Hochstetter, 
states that it ascends this mountain to above 6000 feet. 

Euphorbia azorica, Hochst. — Commencing to flower in the middle 
of March 1913. 

Euphorbia mellifera, Ait. { = E. stygiana). — Recorded from all 
islands except Graciosa, San Jorge, Terceira, and Santa Maria, but 
doubtless it exists or did exist there. According to Seubert it grows 
in the mountain ravines of Fayal and Flores at elevations of 2000 
to 3000 feet. On Pico it grows usually between 3000 and 4000 feet. 
Often grows sporadically, when it may attain a height of eleven or 



THE AZORES 



429 



twelve feet; but sometimes gregariously, when it is usually three 
to six feet high and may form thicket-like growths. 

Hedera canariensis, W. — Fruits in winter as with our English 
species. Observed in mature black fruit in February and up to the 
end of March. The fruits had all fallen by the end of June. Evi- 
dently, therefore, as with our Ivy, they fall in April and May. On 
Pico it may reach as high as 3500 feet, but it is most characteristic 
of the Faya zone, that is, below 2500 feet. 

Hypericum foliosum, Ait. — Flowers in June and July. The 
empty fruits remain on the plant during the winter and spring. 
Plants in full bloom in June may still carry the old fruits of 
the previous year. Typical of the lower woods, that is, below 
2000 feet. 

Hydrocotyle vulgaris, L. — First recorded from the group by Trelease 
from Flores in 1894. I found it in 1914 to be one of the most abun- 
dant plants on the moist upland moors of Pico, 2000 to 4000 feet above 
the sea. Doubtless it also grows on San Jorge. 

Ilex per ado, Ait. — The " Azevinho" of the Azoreans ; but the word 
is so clipped that it sounds like " Azvi." The time of flowering 
depends on the altitude. Thus in the lower levels this usually occurs 
in April and May, as in Madeira (Lowe) ; but in the high levels in 
June and July. According to Seubert it is in flower in the mountains 
in June when it is in mature fruit in the gardens. However, on 
Pico it was frequently to be observed bearing ripe red fruit at the 
latter end of March, and on one occasion I found the same tree in 
early flower and mature fruit. It is equally characteristic of the 
upper and lower wood zones of Pico between 1000 and 5000 feet. 
According to Seubert and Hochstetter it grows in the higher levels 
of all the islands, and on Pico at 4000 to 5000 feet. The genus, 
though so widely distributed over the world, seems rarely to occur 
in oceanic islands. It would appear that the distribution of the 
primitive family type over the Pacific took places ages since, and 
that with the breaking up of the connections through the failure 
of the dispersing agencies differentiation has been induced. Thus, 
although no species of Ilex is known from the islands of the tropical 
Pacific, they possess in Byronia another genus of the family which 
they share exclusively with Australia, Hawaii holding one species, 
Tahiti another, whilst Australia claims a third. 

Ipomcea carnosa, R. Br. — See p. 218. 

Isoetes azorica, D. — This species was first catalogued by Watson 
as /. lacustris. Since the genus was once regarded as monotypic 
and later as holding a few species, whilst at the present it is credited 
with more than fifty species, there is room for the view that the 
larger conception of the specific value may be the most correct. 
The plant was first found by Watson on Corvo in 1842. After more 
than half a century (1894-6) it was rediscovered there by Trelease, 
whilst his son found it on Flores. The present writer discovered 
it in the lake district of Pico in 1914. In all probability it grows 
on San Jorge. That curious association of Isoetes with Littorella 
at the borders of a pond or lake, which has so often been remarked 
in other parts of the world, is to be observed on Pico. There are 



430 PLANTS, SEEDS, AND CURRENTS 



some points of resemblance between two types of plant life, otherwise 
so widely divergent from each other, notably the similarity in general 
appearance between the aquatic long-leaved forms. From the 
standpoint of dispersal one inference seems permissible, namely, 
that the two plants reached the Azores in a similar manner. From 
this arises the implication that the Isoetes spores were not brought by 
the winds, but, like the small seed-like fruits of Littorella, in mud 
adhering to aquatic fowl. 

Juniperus oxycedrus (var. brevifolia, Hochst.). — The " Cedro " 
of the islanders. We learn from Seubert and Drouet that this tree 
was especially frequent on Flores where the largest individuals 
occurred. It would seem that it matures its fruit in the autumn. 
But the data at my disposal do not decide this point. Aiton in his 
Hortus Kewensis speaks of J. oxycedrus as " the brown-berried 
Juniper," and this name would apply also to the Azorean variety, 
the ripe fruits rarely colouring and then only to a slight extent. On 
Pico in March, June, and July, full-sized fruits were often abundant. 
On the higher slopes of Pico da Vara (San Miguel) fruits were scanty 
on February 23. Evidently the fruits often remain on the trees 
during the winter, probably those that fail to mature by the autumn. 
In this respect one may note that Sernander (pp. 321, 328, etc.) 
places Juniperus communis amongst the numerous Scandinavian 
plants that are most actively dispersed in the winter on account of 
the fruits remaining on the tree. Strange to say, the greatest display 
of fruit in the case of the Azorean Juniper was exhibited on April 1 
on the snow-covered upper slopes of Pico at an altitude of 5200 feet. 
Two old trees, about ten feet high and standing all alone, were 
simply laden with full-sized fruit carrying mature seeds and in some 
cases slightly coloured. 

The vertical range of the Azorean Juniper on the slopes of Pico 
was placed by the Hochstetters at 2500 to 5000 feet. This fairly 
represents the usual limits. But in the dwarfed semi-prostrate 
condition I found it scrambling up the lava slopes on the eastern 
side to nearly 6000 feet ; whilst it would be more correct to place the 
lower average limit at 2000 feet, though it may occur sporadically 
as low as 1200 or 1300 feet. Off the mountain the Juniper is 
most at home in the lake district of Pico. There, at altitudes 
of 2500 or 2600 feet, it attains a greater size and exists in larger 
quantity than on the slopes of the cone where it is to be found best 
represented in the upper woods of the eastern slopes about 4000 
feet up. 

There has been much discussion as to the relation of the Azorean 
Juniper to Juniperus oxycedrus of South Europe. But Seubert 
and Hochstetter designated it as a variety of the European species 
under the name of " brevifolia." There seems a great deal to support 
the view of Seubert that it stands to J. oxycedrus as J. nana does 
to J. communis. Let us take the case of the last named. Scott 
Elliot in Botany of To-day (1910, p. 94), writes as follows in this 
connection. " In the lowland districts this is a large shrub or small 
tree, which is occasionally thirty feet high. But in the mountains 
it becomes a dwarf form (J. nana), which is seldom one foot high. 



THE AZORES 



431 



If one cultivates J. nana in the lowlands, as has been done both in 
the Berlin and in the Zurich botanical gardens, it changes into 
Juniperus communis. This has been tried both with seeds and by 
transplanting a mature specimen (Kirchner)." Baron von Mueller 
in his Select Extra-Tropical Plants (p. 170) writes that under favour- 
able circumstances J. communis may attain a height of nearly fifty 
feet. 

The behaviour of J. oxycedrus is much the same. In South Europe 
it rarely exceeds the dimensions of a bush, five or six feet high. 
Yet Hooker in his book on Marocco (p. 252) refers to the occurrence 
at an altitude of about 3500 feet on the slopes of the Great Atlas 
of "an old weather-beaten trunk measuring about five and a half 
feet in circumference and seemingly of high antiquity." In Madeira, 
as we are told by Mr. J. Y. Johnson (Encycl. Brit. 9th edit., XV., 180), 
J. oxycedrus was formerly abundant and grew to a height of forty 
or fifty feet. It is, therefore, highly probable that under the favour- 
able conditions for forest growth which evidently prevailed in the 
Azores at the time of their discovery, the present Juniper trees, which 
do not usually exceed ten or eleven feet high, may have attained 
the great dimensions attributed in the pages of the historians of 
the group to the " cedros " of the original forests. 

But the points we are most concerned with here are the shortening 
of the leaves in the present Azorean Junipers and the validity of 
regarding this feature as a specific distinction. The matter is thus 
stated by Watson (p. 224) : " The leaves (of the Azorean plants) 
are wide and blunt in comparison with those of the South European 
Oxycedrus, and only half their length." From somewhat limited 
materials at his disposal he formed the opinion that the Azorean 
Juniper seems a wider divergence from the European Oxycedrus 
than are the Junipers of Madeira and the Canaries, the transition, 
however, being slight from the Azorean to the Madeiran form and 
from this again to the Canarian form. However, it stands as a peculiar 
Azorean species in the Index Kewensis, and Prof. Parlatore takes 
the same view in De Candolle's Prodromus. The same view is 
taken, according to Trelease, by Antoine in his Kupressineengattungen. 

I will now give my own observations. On Pico I found that 
there were two forms of the plant connected by intermediate stages, 
the one with short obtusely pointed leaves tending to lie close to 
the stem, and near the " brevifolia " type, the other with long almost 
linear acutely pointed leaves tending to spread away from the stem, 
and near the " oxycedrus " type. As regards the position and relative 
length and breadth of the leaves these are also the characters, as 
indicated by a figure after Warming given in Schimper's Plant 
Geography (p. 36), which distinguish J. nana from the ordinary 
type of J. communis. 

On the wind-swept upper slopes of Pico da Vara in San Miguel, 
where the plants are much dwarfed, I found the short-leaved type 
prevailing. In the Carreiro herbarium in the Municipal Library 
at Pont a Delgada there are short-leaved specimens from Pico de 
Vara and long-leaved specimens from Siete Cidades. On the slopes 
of Pico I often found the two forms associated in the same locality 



432 



PLANTS, SEEDS, AND CURRENTS 



together with the intermediate forms. Subjoined are some measure- 
ments of leaves made on dried specimens. 

Long-leaved form from Pico, length and breadth of leaf, 9-9-5 x 1*5 mm. 



Schimper (Ibid.) refers to Warming's view that the tendency of the 
leaves of the form nana of J. communis to be appressed to the stem 
as compared with those of the common form, where they stand apart 
from it, illustrates a method of protection against transpiration. 
My data indicate that the appression and shortening of the leaves 
is most characteristic in the Azores of the dwarfed plants on wind- 
swept mountains. The most typical forms of the long-leaved or 
Oxycedrus type on Pico grew in relatively sheltered situations, 
whilst the plants found in exposed localities at altitudes of 5000 
feet and over belonged for the most part to the intermediate and 
short-leaved types. Viewing the " brevifolia " variety as an adapta- 
tion to the inclement climatic conditions of the higher levels of the 
Azores, it is quite likely that the typical long-leaved, or Oxycedrus 
type, largely disappeared with the destruction of the timber forests 
that originally clothed the lower slopes of the islands. 

Laurus canariensis, Webb (= Persea azorica, Seubert). — The 
" Louro " or " Loro " of the Azoreans and Canarians. Flowers 
profusely in the Azores. According to the observations of the Hoch- 
stetters and of Drouet it is in full bloom in May, but, as I found on 
Pico and San Miguel, in 1913, the process may begin in March. It 
is in green fruit in July, and probably matures its fruit in August. 
The Hochstetters restrict it to the lower mountain woods of Pico 
between 1000 and 2500 feet; but I found it to be also abundant 
in the upper mountain woods, which extend to 4500 feet. Its usual 
range on Pico is 1000 to 4000 feet, but it may extend to nearly 5000 
feet. In the upper levels it is much dwarfed, the tree attaining its 
greatest size in the lower levels (1000 to 2000 feet). On San Miguel 
it occurs as a stunted growth at an elevation of 3000 feet. 

Littorella lacustris, L. — First recorded by Watson from Corvo in 
1842, but not again collected in the group until 1914, when I found 
it in abundance on Pico. That it exists on San Jorge is highly 
probable. 

Lysimachia nemorum, L. — Under the name of L. azorica, Hornem., 
this was at first regarded as a distinct species, and it was so viewed 
by Watson, though he speaks of it as nearly allied to L. nemorum. 
However, the two are united in the Index Kewensis as well as in the 
monograph by Pax and Knuth on the Primulacece in the Pflanzenre ick 
series (1905). During the last half of March 1913, on the slopes 
of Pico, I found it in leaf and fruit, but rarely in flower. In June 
and July of the following year it was abundantly in flower. It is 
one of the most characteristic plants of the upland moors of Pico, 
2000 to 4000 feet ; but when it finds protection in the beds of Heather 
(Calluna) it may extend far up the steep lava slopes of the mountain, 
even to 5600 feet. Seubert, who, it may be remarked referred it to 



Intermediate 
Short-leaved 
Short-leaved 




THE AZORES 



433 



the Linnean species, adopts Hochstetter's altitudes of 1000 to 3000 
feet. 

Menziesia polifolia, Sm. — In the first week of April on the slopes 
of Pico it merely carried the last year's dried fruits with seeds. In 
June and July it was in abundant bloom. Though it occurs in the 
greatest profusion on the scantily vegetated lava slopes of the central 
cone, extending from 5000 feet to the summit, it is also a characteristic 
plant of the higher levels of the upland moors 3000 to 4000 feet and 
may reach down to 2500 feet. Hochstetter refers it to the highest 
zone on Pico, namely, above 5000 feet, and it is certainly most typical 
of those levels. Though probably distributed over nearly all the 
islands from Terceira westward, it has apparently not been recorded 
from either San Miguel or Santa Maria, the two easternmost and 
best-explored islands of the group. 

Myrica fay a. — Flowers according to Seubert in May and June. 
On Pico it ripens its fruits at end of July and in August. Trelease 
in his list of localities names all the islands except Terceira and San 
Jorge. I found it on the first named, and recognised it on the steep 
slopes of San Jorge from the steamer's deck. It is one of the most 
characteristic trees of the lower woods of the Azores, and Seubert 
remarks (following Hochstetter) that it occurs on all the islands 
up to 2000 feet. This, as I found, is the usual upper limit both on 
Pico and on San Miguel, and where it extends three or four hundred 
feet higher it no longer forms a conspicuous feature of the vegetation. 
At times one may find it growing in the bottom of a deep gulch 
higher up the slopes of Pico. Thus I noticed it growing under these 
conditions at an altitude of 3300 feet, where it had found protection 
from the prevailing strong winds at these heights. My guide was 
much surprised, and on his pointing out to me the usual upper 
limit of the tree I found it to be about 2000 feet above the sea. It 
descends to the coast, where it may be seen on old lava-flows and on 
steep declivities. The island of Fayal is said to have derived its 
name from this tree ; but there is a coast village of the name at the 
south-east corner of San Miguel; and a town, river, headland, 
and islet on the north-east coast of Madeira are thus called. The 
Azores were occupied by the Portuguese about thirty years after 
the occupation of Madeira in 1420, and the connection between the 
tree-name and the place-name is by no means free from doubt. 

In Lacerda's Portuguese and English Dictionary (1871) " Faia " 
or " Fay a " is the proper name for the Beech, and " Faial " is 
" a place where beech trees grow, or a plantation of beech trees." 
Prof. Henriques, who very courteously replied to my queries in the 
matter, tells me that Fagus sylvatica is not met with in Portugal. 
It is, however, curious that George Forster, who visited the island 
of Fayal in the Resolution in 1775, speaks of the " great quantities 
of beeches called faya," naming the genus Fagus (Voyage round the 
World, 1777, II., 581-604). In Portugal, as Prof. Henriques in- 
forms me, Myrica faya is known as " Faia das ilhas," or " Faia of 
the Isles." 

This brings me to remark that this tree has long been established 
in different parts of Portugal. Indeed, Dr. Christ in his paper on 



434 PLANTS, SEEDS, AND CURRENTS 



the Canarian flora (Engler's Jdhrbucher, bd. VI., 1885) apparently 
implies that it is indigenous in the Portuguese mountains. Prof. 
Henriques, who tells me that possibly we might to-day consider it 
as almost indigenous in the mountains of Algarve, the southern pro- 
vince of Portugal, gave me Brotero's reference to it in the Flora 
lusitanica : " Hab. quasi spontanea in pineto regione circa Leiria, 
Cintra, etc., ex insula Fayal et aliis Azoricis advecta." B. A. Gomes 
and Da S. Beirao in their catalogue of the plants in the botanic 
garden of the medical school of Lisbon (1852) speak of Myrica faya 
as the " Faya of the Isles " and under its habitat name Madeira, 
the Azores, and Algarve in Portugal. Here 44 Faya " is also given 
as the name of two European species of Poplar, Populus alba, 
the 44 Faya branca " or 44 White Poplar," and P. tremula (nigra, 
H.B.G.), the 44 Faya preta " or 44 Black Poplar." They also speak 
of 44 Samoco " as another Portuguese name of Myrica faya, a name 
also supplied to me by Prof. Henriques; but I can find nothing 
about its significance. 

Myrsine africana, L. — The 44 Tamujo," or 44 Tamucho," or "Tamuzo" 
of the Azoreans, the final vowel being dropped in the vernacular. 
The early Portuguese colonists evidently gave it the name of plants 
of similar appearance in their home-land. In Portuguese and Spanish 
dictionaries the name is applied to Rhamnus lycioides, but Prof. 
Henriques tells me that in Portugal it is given to Securinega buxifolia. 
The earlier botanists regarded the plant as a species of Buxus, and 
its appearance might suggest it. 

Watson and Trelease refer it to the variety retusa of De Candolle ; 
but this variety is not differentiated by Mez in his work on the 
Myrsinaceo? (Pflanzenreich, 1902). It flowers in April and May 
(Seubert). Evidently the shrub bears the ripening fruit through 
the winter. In the Furnas Valley at the end of February I found 
it in nearly mature fruit. Druce, who visited this locality in March, 
speaks of the plant's copious berries covered with bloom (Journ. 
Bot., Jan. 1911). On Pico in the latter half of March it was fre- 
quently observed by me in mature fruit. At the end of June and 
the beginning of July it carried only immature green fruit. These 
shrubs begin to appear on Pico about 600 or 700 feet above the sea. 
Though abundant in the Faya zone, that is, below 2000 or 2500 feet, 
it extends in quantity considerably higher, as far, in fact, as the upper 
woods go, namely, to 4000 or 4500 feet; and in a dwarfed form it 
ascends in places the steep lava slopes of the central cone, the extreme 
altitude noted being 5200 feet. Hochstetter's observations gave 
similar results, since he places it in the lower and upper woods ranging 
between 1500 and 4500 feet. It grows in a stunted form on the 
summits of the principal mountains of San Miguel, the highest of 
which rises to nearly 3600 feet. 

Osmunda regalis, L. — Recorded in Trelease' s pages from Corvo, 
Flores, Fayal, Terceira, and San Miguel. I found it characteristic 
of Pico ; but although seemingly Seubert did not include this island 
in his list of localities, this fern is named (p. 6) amongst the plants 
characterising the lower mountain woods of Pico. It was in these 
woods at altitudes ranging from 1200 to 2500 feet that this fern 



THE AZORES 



435 



often came under my notice, both on the great mountain and in the 
lake district to the east of it. In all probability Osmunda also 
grows on San Jorge. 

Per sea indica, Spr. ( = Laurus indica of Lowe's Madeiran flora). — 
The " Vinatico " of the Azores and Madeira. Evidently exists or 
did exist in nearly all the islands of the Azores ; but there is a doubt 
about its nativity. Seubert, who was dependent on the Hochstetters 
for his information, does not mention it; and Watson remarks that 
as seen by himself in Fayal and Flores the tree had a questionable 
claim to be considered indigenous. However, Drouet refers to entire 
woods of it in the other islands. Trelease gives no opinion on the 
matter; but the symbol used indicates that he regarded it as indi- 
genous. Yet, considering that the tree is entirely confined to the 
Macaronesian islands, it would not be a subject for surprise if it was 
indigenous in the Azores as well as in Madeira and the Canaries. 
We have seen that a number of peculiar Macaronesian species (Ilex, 
Rhamnus, Picconia, Laurus, Myrica, etc.) give a common character 
to the woods of all the three groups and the exclusion of this handsome 
tree from the list can on this ground scarcely be justified. I found 
it growing commonly in colonies in the woods at the back of Magda- 
lena, Pico, two miles inland, and 600 to 800 feet above the sea. The 
trees, fifty feet in height, were in early fruit in the latter part of March, 
whilst great numbers of the previous year's seeds lay germinating 
on the ground beneath the trees, often forming seedlings five or six 
inches high. Solitary trees are to be noticed in the gardens. As 
elsewhere observed, the fruits are a favourite food of Azorean and 
Canarian pigeons. 

Picconia excelsa, DC. ( = Notelcea excelsa, Webb). — The " Pao 
branco " of the Azores and Madeira, and the " Palo bianco " of the 
Canaries. Seubert states that this tree flowers in May. I found it 
on Pico in flower in April. It probably exists or did exist on all the 
islands; but its hard timber is much appreciated by the Azoreans, 
and on the mountain of Pico it only escapes destruction by taking 
refuge in some inaccessible gulch or small crater. I only came 
upon three or four solitary trees in the woods of the great mountain 
of Pico at altitudes of 1000 to 2000 feet. They are said to be more 
frequent off the mountain, as on the slopes above Lagens. Seubert, 
whose work is concerned with the Azorean flora in the first half of 
last century, alludes to this tree as a constituent of the lower mountain 
woods of Pico, that is, below 2500 feet, and as occurring in nearly 
all the islands at elevations of 2000 to 3000 feet (Hochstetter), though 
rather uncommon. Drouet remarked that in his time (1857) it 
was more frequent on Santa Maria than elsewhere. In some islands, 
as in San Miguel, where it used to be planted with the Faya for the 
protection of the Orange trees (Seubert), it was, however, truly 
native (Hunt quoted by Watson). Lowe states that it is very 
rare in Madeira, growing to a height of forty to sixty feet, one or 
two trees together. It there flowers, February to July. Fruits, 
August to September. 

Polygala vulgaris, L. — It is remarkable that this plant has only been 
found in the Azores on the island of Pico. Since it was collected 



436 PLANTS, SEEDS, AND CURRENTS 



there by the Hochstetters in 1838 no other botanist has discovered 
it in any of the other islands. Its vertical distribution on the great 
mountain is stated in Seubert's work, from information supplied 
by Hochstetter, to range from 4000 feet almost to the summit. 
However, I found it at lower levels. It is a characteristic plant of 
the upland moors and of the grassy intervals in the open woodlands 
between 3000 and 4000 feet, and it grows under the same conditions 
off the mountain in the lake district to the eastward at an altitude 
of 2500 feet. On the exposed higher slopes of the great cone, amongst 
the ashes and the old lava-flows, it seeks the protection of the beds 
of Calluna vulgaris, and in this manner reaches almost to the summit. 
Details of its occurrence in these high levels are given on previous 
pages. It in all probability grows on the uplands of San Jorge. 

Rhamnus latifolia, L'Her. — The " Sanguinho " of the Azoreans, 
a name suggested by the reddish hue of the wood. This small tree, 
which behaves in winter as a sub-evergreen, apparently retaining 
its summer foliage in the mild winter, attains a height usually of 
ten to fifteen feet, at times reaching twenty feet. It flowers in May 
and June, and matures its fruit in July and August. In Seubert's 
work it is stated to be common in the woods of all the islands, extend- 
ing up to nearly 3000 feet, and in the zones of vegetation on Pico, 
which he gives (p. 6) from the notes of the Hochstetters, he places 
it in the lower- woods zone, that is, below 2500 feet. This corresponds 
with my own observations on the mountain, where I found it most 
typical of the lower woods below 2000 feet, but frequently reaching 
to 3000 feet. It shows itself shortly after one passes the cultivated 
zone in the ascent of the mountain, namely, at 1000 feet. The 
island of Pico is not mentioned in Trelease's list of localities, which 
include Flores, Fayal, San Miguel, and Santa Maria; but, as has 
just been implied, it was found there by the Hochstetters as far back 
as 1838. Low T e, writing in the middle of last century, indicates that 
in Madeira it was then apparently extinct as a wild plant. 

Sibthorpia europcea, L. — Distributed over the group. Common in 
the upland moors of Pico between 2000 and 4000 feet and extending 
at times to nearly 5000 feet. Hochstetter gives it an altitude of 
about 4000 feet on Pico. It occurs on the summit of Pico da Vara, 
the highest point of San Miguel, 3570 feet above the sea. On Pico 
it was in flower and fruit in July, the flowers examined having five 
calyx segments. Several years ago I kept some English plants 
under observation in South Devon. Both out of doors and under 
cover most of the fruits failed to mature, and only a few dehisced, 
behaviour which seems to indicate the northern limit of the climatic 
conditions suitable for the species. 

Taxus baccata, L. — The " Teixo " of the Azoreans. Watson re- 
marks that he had no confirmation of its existence in the mountains 
of these islands, alluding to a report to that effect mentioned by 
Seubert. However, Drouet refers to it as growing in 1857 on Flores, 
but beginning to be rare, the wood being much valued by cabinet- 
makers. Trelease, who visited the group forty years later, writes 
that it " formerly occurred in workable size on Corvo and Flores, 
whence it was exported as a source of royal revenue. Now seemingly 



THE AZORES 



437 



exterminated." However, it still exists in the island of Pico. In 
1914 I came upon a few young trees in the woods at the back of 
Caes-o-Pico at an altitude of nearly 2000 feet, and was informed that 
more grew on the sides of gulleys in the mountains behind San 
Roque, which lies a little more to the east. The Pico islanders are 
familiar with the tree by reputation, though as it has long been 
very scarce, but few could have seen it growing in the woods. In 
fact, the tree was first described to me on the other side of the island 
by men who knew it only by reputation as supplying good timber 
for houses. At Praynha do Norte I was told that up to recent times 
the wood of the " Teixo " was to be seen in a few of the oldest houses. 
As already remarked a lake in the mountains behind San Roque is 
still known by some as the " Lagoa das Teixas " (Taxus), though 
the tree must be almost extinct there now. According to Walker 
the old Portuguese historians of the group of the sixteenth century, 
and Linschoten at its latter end, described the Teixo as abundant 
on Pico. Linschoten especially noticed that this Pico tree was 
known for its " excellent and princely wood." Coming down to 
later times, Dr., Webster in his Description of the Island of St. Michael, 
Boston, 1821, writes that " the wood of Pico appears to be a species 
of yew. Considerable quantities were formerly sent to Lisbon, 
where it was manufactured into work-tables, desks, etc." (p. 214). 

Lowe includes Taxus haccata amongst the indigenous trees of 
Madeira ; but it is characterised by him in the middle of last century 
as being very rare. 

As regards the dispersal of this tree by birds, reference is made in 
an article in the Times on Bird Gardeners (October 16, 1915) to the 
distribution of the fruits of churchyard Yews in Breconshire by 
missel-thrushes, which drop the undigested seeds on rocky crags 
a thousand feet up the mountain slopes, where young Yews sub- 
sequently spring up. These birds, according to Ogilvie-Grant 
(Novit. Zool, XII., Jan. 1905), are very rare stragglers in the Azores. 

Vaccinium cylindraceum, Sm. — The " Romano " or 44 Romani " of 
the Azoreans. Flowers in May and June. Begins to form fruit 
in the latter half of July and matures it in August. Seubert, relying 
on Hochstetter, gives its vertical range on Pico as 1000 to 5000 feet. 
This exactly corresponds with my observations. Above 4000 feet, 
when it ascends the scantily vegetated precipitous lava slopes, it 
becomes stunted; and at the highest levels observed, 5000 to 5200 
feet, it found shelter in the Calluna beds, where it was only a few 
inches high. In the woods it often attains a height of nine or ten 
feet, and when particularly luxuriant in its growth, as in the humid 
plains of the lake district, it may reach fifteen feet ; but it is then 
almost straggling in its habit. 

Viburnum tinus, L. — The Laurestinus of our gardens. In England 
it flowers in midsummer and midwinter, and evidently it fruits 
twice in the year, namely, at the end of summer and in April. Arcan- 
geli states that it flowers in the Mediterranean region in January 
and August. In the Azores according to the observations of Drouet 
and myself it flowers in April and May, showing the early flower- 
buds at the end of February and in March. It ripens its fruits in 



438 PLANTS, SEEDS, AND CURRENTS 



the end of June and in July. But since on the higher slopes of the 
mountain of Agua do Pao (San Miguel) it presented itself in mature 
fruit as well as in early flower-bud at the end of February, it would 
seem that there may be a second flowering in the early winter, 
though I fancy that this is exceptional. Trelease apparently found 
the plant in fruit in summer. 

Seubert, relying on Hochstetter, states that it occurs in the moun- 
tain woods of the Azores between 1000 and 2000 feet. This corre- 
sponds with the results of my observations on Pico, where it ranges 
from levels of 700 or 800 feet, where the cultivated zone gives place 
to the lower woods, up to 2000 feet. On the slopes of Agua do 
Pao in San Miguel it ascended to 2500 feet, but in the condition of 
scrub. As Seubert observes it is rather uncommon in the group, 
but I may add that it is frequent in places. Seubert (1844) gives 
Fayal and San Miguel. Watson (1870) adds Flores and Corvo. 
Trelease adds Santa Maria, and I have added Pico. When San 
Jorge is better known botanically, the existence there of this shrub 
will probably be established. On Pico it seems to be far from 
abundant. Only at times one comes upon it in the wooded region 
at the western end of the island; but it is fairly frequent in the 
vicinity of Cabeza Grande. On the south side, corresponding to 
the great mountain, it may perhaps be rather more frequent; but 
it is never generally distributed. My notes contain no reference to 
it either on the other slopes of the mountain or in the lake district 
to the eastward. 

Its leaves are subcordate and broader and more obtuse than 
European specimens; and Trelease distinguishes it as an Azorean 
variety, subcordatum, remarking that it is apparently more closely 
related to the Canarian V. rigidum than to V. tinus of the Mediter- 
ranean region. Probably the Canarian species is a derivative of 
that species (H.B.G.). 

Summary 

1. Before dealing with the modes of dispersal of the plants of 
the Azores, it is observed that whilst the connection between the 
plants of the woods of this group and those of Europe is either broken 
or breaking, it is still kept up with Madeira and the Canaries. In 
the case of the plants of the mountain moors and of those of the 
ponds and lakes the connection with Europe has been sustained 
down to recent times (p. 417). 

2. The plants of the woods would in most cases be dispersed by 
frugivorous birds, such as pigeons ; and it is remarked that the break- 
ing of the link with their European home, as indicated by their specific 
or varietal differentiation, corresponds with the subspecific or varietal 
differentiation of the pigeons of the Macaronesian islands (p. 418). 

3. The minute seeds or small seed-like fruits of the plants of the 
upland moors would probably be transported in mud adhering to 
birds' feet or in their plumage. The capacity possessed by Luzula 
and J uncus seeds of sticking firmly to a bird's feathers after being 
wetted is observed; but it is remarked that these small-seeded 
plants often raise other questions than those of dispersal (p. 419). 



THE AZORES 



439 



4. In the case of the aquatic and subaquatic plants it is shown that 
whilst those with small seeds, such as Peplis, Littorella, etc., would 
be dispersed by waterfowl that would be likely to carry dried mud 
on their feet and legs, others like Potamogeton, Car ex, Scirpus, etc., 
possess small fruits that are known to be swallowed and ejected 
unharmed by waterfowl (p. 420). 

5. As in temperate latitudes, currents have not taken a prominent 
part in stocking the seashore plants of the Azores with their plants,., 
unless we include the intermediate agency of the drifting log; and: 
appeal is made to a variety of other dispersing agents (p. 420). 

6. In regard to the strenuous appeal of Wallace for the paramount 
influence of winds over birds in transporting small seeds like those 
of Sagina and Orchis over tracts of ocean 1000 miles in width, it is 
remarked that although there seems to be no question about the 
fitness of the spores of cryptogams for dispersion by winds across 
the ocean it is concerning the seeds of flowering plants that doubts 
would be raised. In this connection the results of the experiments 
of Lloyd Praeger on the falling rates of seeds are utilised to show that 
the great contrast in weight between the smallest seeds of flowering 
plants and the spores of cryptogams reflects the difference between 
inefficient and efficient dispersal by winds over great distances. 
Though so minute in size and so light in weight, the seed of an orchid 
falls through the air at least fifty times as fast as an ordinary mush- 
room spore. To counteract the effects of gravity, as measured by 
the falling rates of seeds and spores, an initial elevation at the starting- 
place must be assumed ; and it is shown that before a wind blowing 
at the speed of fifty miles an hour, the initial altitude requisite for 
a spore or seed to reach the Azores from the European sea-borders ; 
would be only a few hundred feet for a mushroom spore and nearly' 
ten miles for an orchid seed. It is shown, however, that witfcu 
" plumed seeds," such as those of Typha and Epilobium, the difficulty 
is not quite so great; but even here an initial elevation of 20,000 
feet would be required in the first case and of 35,000 feet in the second 
case to reach the Azores. It is urged that the up- draught on the 
slopes of lofty mountains would provide the initial altitude for 
cryptogamic spores and perhaps also for plumed seeds of the types 
above named. But this would be impossible both for the seeds of 
orchids and for the pappus-fruits of Composite plants, like Senecio 
and Sonchus, where initial elevations of nine or ten miles would be 
needed (p. 422). 

7. The last part of the chapter is devoted to notes on the plants 
of the Azores (p. 425). 

LIST OF WORKS DEALING WITH THE PLANTS OF THE AZORES OR 
QUOTED IN THE DISCUSSION IN THIS AND THE TWO PRECEDING 
CHAPTERS 

(See also list of works on Azorean botany in Trelease's paper below mentioned.) 

Ball, J.,. The Mountain Flora of the Great Atlas, given in Hooker's book on Marocco 

below named. 
Beirao, C. M. F. da S. See under Gomes. 
Boid, Description of the Azores : London, 1835. 



440 PLANTS, SEEDS, AND CURRENTS 



Bullae H } A Winter in the Azores : London, 1841. 

Caedot, J., The Mosses of the Azores, Eighth Annual Report of the Missouri Botanical 

Garden : St. Louis, 1897. 
Chaves, F. A., Gisements de Diatomees fossiles a Furnas (He de S. Miguel), Bull. 

de la Soc. Portug. des Sci. Nat., II., 1909 : Lisbonne. 
Christ, D. H., Vegetation und Flora der Canarischen Inseln, Engler's Botanische 

Jahrbucher, VI., 1885. 
, Spicilegium Canariense, Engler's Botanische Jahrbucher, IX., 1887-8. 

.Drotjet, H., Catalogue de la flore des lies Agores : Paris, 1866. 
LDbuce, G. C., Plants of the Azores, Journal of Botany, January 1911, and in The 
Chemist and Druggist about the same year. 

T?obster, G., Plantse Atlantic* ex insulis Madeirse, S w Jacobi, Adseensionis, S fcae 
Helenae, et Fayal reportatae, Commentationes Societatis Begice Scientiarum Gotting- 
ensis, Vol. IX., 1787 : Gottingse, 1789. 

Godman, F. du C, Natural History of the Azores : London, 1870. (The botanical 

section is by Watson.) 
Gomes, B. A., and C. M. F. da S. Beirao, Catalogus Plantarum Horti Botanici Medico - 

Chirurgicse Scholse Olisiponensis : Olisipone, 1852. (List of plants introduced 

from various parts of the world.) 
«Guppy, H. B., Notes on the Native Plants of the Azores, Bulletin, Boy. Bot. Gard. 

Kew, 1914. 

Hartung, G., Die Azoren : Leipzig, 1860. (Descriptive of the geology of the islands ; 

but about forty pages are devoted to the flora, the materials mainly derived 

from Seubert, Hochstetter, and Watson.) 
Hemsley, W. B. A few remarks on the Azores in a discussion of the floras of the 

Canary and Cape Verde groups, Science Progress, II., 379, 1894. 
Hochstetter, C. See under Seubert. 

Hooker, J. D., Insular Floras, Brit. Assoc., 1866; Marocco and Great Atlas, 1878. 
Hunt, Carew, Descriptions of the islands of St. Mary and St. Michael in the Azores, 
Journ. Boy. Geogr. Soc, XV., 258, 1845. (Botanical remarks are scanty.) 

Linschoten, J. H. van. An account of his sojourn in the Azores, about 1589, is 
given in " Purchas, His Pilgrimes," edit. 1905, Vol. XVIII., derived from the 
original account of his voyages. 

Lowe, R. T., A Manual Flora of Madeira, 1857. 

Masson, F., Account of San Miguel, Philos. Trans., 1778. 
Mayor, F. S., Traveller's Guide to St. Michael's, Ponta Delgada, 1911. 
Morelet, A., lies Agores, L'Histoire Naturelle : Paris, 1860. (Contains valuable 
remarks on the flora.) 

Seubert, M., and C. Hochstetter, Ubersicht der Flora der azorischen Inseln, Wieg- 
mann's Archiv fur Naturgeschichte, Jahrg. IX., band i. : Berlin, 1843. 
Flora Azorica, by Seubert, from the collections and notes " Hochstetteri patris et 
filii": Bonn, 1844. 

'ITeelease, W., Botanical Observations on the Azores, Eighth Annual Report of the 
Missouri Botanical Garden : St. Louis, 1897. 

^Walker, W. F., The Azores, 1886. 

Wallace, A. R. Discussions of the Azorean flora from the standpoint of dispersal 

in his works on Island Life, 1880, and Darwinism, 1889. 
Warnstorf, C, Sphagnacese, Pflanzenreich, heft 51 : Leipzig, 1911. 
Watson, H. C, Botany of the Azores. See Godman above. Also earlier papers 

in the London Journal of Botany, Vols. II., 1843; III., 1844; VI., 1847. 
Webster, J. W., Description of the Island of St. Michael, etc. : Boston, 1821 (mainly 

geological). 



APPENDIX 
List of Notes 

Note 1. The time occupied by bottle-drift in the traverse in the 

Main Equatorial Current from the Gulf of Guinea to the 

coast of Brazil and to the West Indies. 
2. The local beach-drift of the Turks Islands. 
„ 3. The effects of wind-pressure on some of the shrubs of the 

more exposed cays of the Turks Islands. 
„ 4. On the experiments of Prof. Ch. Martins on the effects 

of sea- water immersion on the fruits of Cakile maritima. 
„ 5. The synonymy of Sccevola plumieri, Vahl, and Sccevola 

hcenigii, Vahl. 

„ 6. The strand plants of Teneriffe and of the north-east corner 
of Grand Canary. 
7a. The plant-stocking of islets in the Florida Sea. 

„ 7b. A comparison of the vegetation of sand-islets in the coral- 
reef regions of the West Indies, and of the Pacific and 
Indian Oceans. 

,, 8. The lake of the Grand Etang in Grenada. 

„ 9. Guilandina bonduc and other species. 

„ 10. Mucuna pruriens, DC. 

„ 11. The relation between the floras of Ascension and St. Helena 
and the currents. 
12. Bottle- drift on the Azores. 
„ 13. Bottle-drift in the Turks Islands. 
„ 14. Bottle-drift on the Bermudas. 

15. The circuit of the North Atlantic accomplished by bottle- 
drift. 

„ 16. Traverse of the North Atlantic by the derelict W. L. White. 

„ 17. Mr. Lloyd Praeger's experiments on seed-buoyancy. 

„ 18. The differentiation of the Main and South Equatorial 

Currents in mid- Atlantic. 
„ 19. The Guinea Current. 

„ 20. Bottle-drift from the South-east Bahama seas to the coast 

of Ireland and back. 
„ 21. On some small-seeded West Indian littoral plants. 
„ 22. The Azores and their African connections as illustrated 

by Sphagnum. 
„ 23. Pumice on the beaches of the Azores. 
„ 24. Trailing growth of Anagallis tenella. 

„ 25. Sabine's record of the drifting of casks of palm oil from the 
Gulf of Guinea to Hammerfest. 

441 



442 



APPENDIX 



„ 26. A bottle-drift from Ascension to Guernsey. 
„ 27. Bottle-drift on the Canary Islands. 
„ 28. Bottle-drift on Madeira. 

„ 29. Sargasso or Gulf weed in Azorean beach-drift. 

„ 30. Iguanas, snakes, and alligators in the Turks Islands. 

., 31. Draccena draco (Dragon-tree). 

,,32. A comparison of the old and later charts of the Turks 
Islands. 

„ 33. Plants collected by George Forster in Fayal. 

„ 34. Observations on the medanos or moving sand-hills of the 

Ancon coast region in Peru. 
„ 35. Bottle-drift in high latitudes of the North Atlantic. 
„ 36. The wells of Pico in the Azores. 
„ 37. Uncinia. 

„ 38. The fruiting behaviour of Atriplex portulacoides, L., at 

Salcombe, South Devon. 
„ 39. Recent observations in the western Bahamas by Dr. 

Vaughan and other American geologists. 

Note 1 (p. 70). 

The time occupied by bottle-drift in the traverse in the Main 
Equatorial Current from the Gulf of Guinea to the coast of Brazil 
and to the West Indies. 

Since the data for bottle-drift at my disposal only apply to the 
traverse west of St. Paul's Rocks and Ascension, it will be necessary 
to supply the deficiency from an authoritative nautical publication. 
In so doing we shall be able to compare results obtained by the 
navigator with those supplied by the floating bottle. 

It is highly probable that the drifting bottle in the first half of 
the passage would travel eastward at a greater rate than twenty 
miles a day, which is the average rate to the west of St. Paul's Rocks. 
This is directly indicated in the Admiralty publication, the Africa 
Pilot (Part I., p. 52, London, 1907), where we find the following 
statement : " The Equatorial Current appears to attain its greatest 
volume and velocity during the season of the northern summer. 
From the African coast to about the 15th degree of west longitude, 
the maximum strength, sixty miles a day, has been observed in 
May and June, and during this period its direction is more regular, 
being west (true). Westward of that meridian, at successive later 
periods, or between July and October, it is probably subject to 
irregularities in strength, depending on the winds." 

This current is regarded in the pages of the work above named 
as commencing in the neighbourhood of Anno Bom in the Gulf 
of Guinea. From this locality to the West Indies (Trinidad and the 
neighbouring islands) the distance along the track of the current 
would be about 4000 miles. We can allow for the increased velocity 
in the first third of the traverse from the Gulf of Guinea to the West 
Indies by assuming an average drifting-rate of thirty miles a day 
for a bottle over the whole distance. This gives a result of 133 



APPENDIX 



443 



days, the estimate employed in my table being 118 days. It may 
be remarked that Laughton gives the average velocity of the current 
as twenty to thirty miles a day {Physical Geography, 1873, p. 187). 
A considerably shorter time would be occupied by the current in 
carrying a bottle from the Gulf of Guinea (Anno Bom Island) to the 
coast of Brazil (Cape St. Roque), a passage of about 2500 miles. At 
the average rate of thirty miles a day it would require twelve weeks, 
which is the estimate accepted in this work. 

We will proceed now with the discussion of the bottle-drift materials 
employed in this treatment of the Main Equatorial Current. The 
data may be arranged in the following groups : (a) those supplied 
by the bottles thrown into the sea in the vicinity of Ascension, which 
lies within the current but near its southern border; (b) those data 
concerning bottles thrown into the northern portion of the current 
in the vicinity of St. Paul's Rocks ; (c) those of bottles thrown into 
the centre of the stream between St. Paul's Rocks and Cape St. 
Roque ; (d and e) those of bottles thrown overboard off the Amazon 
estuary. 

(a) The Ascension Area. — Probably the slackest portion of the 
current is near its southern border in the vicinity of Ascension. 
In the case of three bottles thrown overboard on successive days 
in February from a ship on the course between St. Helena and 
Ascension the following minimum daily rates are supplied by Schott 
(pp. 14, 27; Maps I. and IV.) :— 

(1) 11-3 miles from a position half-way between these two islands 

to Paranahiba on the coast of North Brazil. 

(2) 11-7 miles from about 200 miles south-east of Ascension to 

the Lesser Antilles (Grenadines). 

(3) 18-1 miles from a position fifty or sixty miles south-east of 

Ascension to Jamaica (Morant Bay). 

Since the swiftest rate is afforded by the bottle that made by far 
the longest passage (4017 miles), it is fair to conclude that there 
was not the delay in its recovery that there was in the other two cases, 
and probably nineteen or twenty miles a day would represent the 
speed of its passage to the West Indies. It may be added that a 
bottle dropped into the sea about 100 miles north-west of Ascension 
in January 1822, which was picked up on Trinidad, gives a minimum 
daily drifting rate of 15-6 miles (No. 45, Nautical Magazine, 1852). 

(b) The St. PauVs Rocks Area. — Just as Ascension lies a little 
within the southern border of the current, so St. Paul's Rocks lie 
just within its northern border. There are, in the first place, at my 
disposal data for thirteen bottles dropped over in mid-Atlantic 
between the meridians of 22° and 32° W. and the parallels of 5° N. 
and 2° S., most of the materials being supplied by the American 
charts. Of these, nine were stranded on the West Indian islands 
between Trinidad and Martinique (inclusive), giving rates during 
passages of from 1900 to 2400 miles of 20, 19-8 17-2, 16, 16, and 14-4 
miles a day in the six most rapid cases. The two greatest velocities 
apply to bottles that were thrown over in March and November, 



444 



APPENDIX 



the first being especially important, since the bottle was found by 
fishermen afloat off the island of St. Lucia, and the element of un- 
certainty that attends most records of bottle-drift is thus removed 
(Schott, p. 16). Of the other four bottles, one was stranded at 
Cayenne in French Guiana, and three broke through the line of 
islands of the Lesser Antilles, one of them reaching Porto Rico; 
whilst the other two after crossing the Caribbean Sea entered the 
Gulf of Mexico, one of them being stranded at Vera Cruz, and the 
other ultimately arriving at the Florida keys. The last mentioned, 
which was thrown over in the St. Paul's Rocks area in March, per- 
formed a passage of nearly 4000 miles, its minimum daily drift rate 
being computed in the American chart at 18-4 miles. 

Dr. Schott (p. 16) gives an interesting series of records which con- 
firm these results. Of three bottles dropped into the sea on different 
days in January between 0° and 7° N. lat. and 27° and 31° W. long., 
that is to say, in the neighbourhood of St. Paul's Rocks, all were 
found in the following May on different parts of the coast of Trinidad, 
the respective daily rates indicated being 17-7, 17-1, and 17-0 miles. 

(c) The Region between St. PauVs Rocks and Cape St. Roque. — If 
bottles thrown into this current in mid- Atlantic near its northern 
and southern borders are carried to the West Indies at the rate of 
nineteen or twenty miles a day, it is likely that in the centre of the 
stream they would attain a greater velocity. Dr. Schott (p. 16) 
gives the rates for seven bottles placed in the sea during February, 
March, and April, between St. Paul's Rocks and Cape St. Roque, 
or a little to the eastward, namely, between the parallels 0° and 7° S. 
and the meridians 27° and 32° W. They were all recovered on Trini- 
dad and the adjacent island of Tobago, four of them giving minimum 
daily rates exceeding twenty miles, the greatest being 27-2 miles. 
We may take them as indicating an average velocity of at least 
twenty-five miles during this part of the passage, and if we allow 
for the " speeding up " of the current on approaching the Brazilian 
coast it is probable that the average velocity of the thread of the 
current in the latter half of its traverse to the West Indies would 
be nearer thirty miles a day. 

(d) Off the Amazon Estuary and thence to the West Indies. — Accord- 
ing to the known behaviour of this powerful current, its speed in- 
creases greatly after passing Cape St. Roque, and we should expect 
that bottles cast into the sea off the mouths of the Amazon would 
be transported to the West Indies at a rate of from thirty to fifty 
miles a day. The data for nine bottles, mostly derived from the 
American charts, are here employed. They were thrown over in 
March, April, and May of different years at a distance of from 200 
to 300 miles from the mouths of the Amazon. As indicated by the 
dates of their recovery on Trinidad and Tobago three of them per- 
formed the passage of from 900 to 1100 miles at minimum daily 
rates of 43-5, 36-1, and thirty-four miles. But the greatest velocity 
recorded for a bottle thrown into the sea in this locality was attained 
by one that was recovered on the Virgin Islands twenty-eight days 
after its start, having accomplished a drift of 1400 miles at fifty miles 
a day. This bottle was cast over with two others on the same day 



APPENDIX 



445 



and in the same locality, about 200 miles off the Amazon estuary, 
its two associates being afterwards stranded on Trinidad, the mini- 
mum daily rates recorded being 43-5 and 36-1 miles (U.S. Chart 
for the N. Atlantic, May 1909). The behaviour of these three bottles 
is most instructive. Evidently there was considerable delay in 
their recovery on Trinidad, ?r and very little delay in the case of the 
one that reached the Virgin Islands. We should probably, therefore, 
not go far wrong if we assumed that in the last part of its oceanic 
passage along the coasts of North Brazil and the Guianas the Main 
Equatorial Current carries bottle-drift to the West Indian region 
at the average rate of forty miles a day. 

(e) Off the Amazon Estuary and thence to the Florida Coasts. — With 
reference to the time occupied by drift in the passage from the 
vicinity of the Amazon estuary to the Florida seas the following 
data may be employed. The track assigned in both the American 
and German maps to bottles that arrive on the coasts of 
Florida from latitudes in the tropical Atlantic south of 10° 
N. lies across the Caribbean Sea and through the Straits of 
Yucatan. This is well illustrated by the drift of two bottles that 
were dropped into the sea on the same day of April within twenty- 
five miles of each other and about 130 or 140 miles off the coast of 
French Guiana, the details of which are given in the U.S. North 
Atlantic chart for May 1909. One was recovered in the Gulf of 
Honduras 111 days afterwards, the distance of 1920 miles being 
covered at a minimum rate of 17-3 miles a day (not 27-3 miles as 
stated in error in the chart). The other was found on the east coast 
of Florida north of the Straits in lat. 26° 56' N. Up to the date of 
recovery 182 days had passed and the minimum rate over a distance 
of 2640 miles is placed at 14-5 miles a day. Very remarkable is 
it that a third bottle thrown over on the following day from the same 
ship in lat. 10° N., and about six degrees east of Trinidad was recovered 
143 days afterwards in the same place on the Florida coast, the 
estimated minimum rate over a distance of 2400 miles being 16-8 
miles a day. Since the bottle was recovered thirty-eight days before 
the other, which was found in the same locality, it is probable that 
it was picked up with but little delay. 

Another record from this part of the Atlantic, though evidently 
a belated one, concerns a bottle thrown over from the Prince Eugene 
in March, about 300 miles north-east of the mouths of the Amazon. 
It has already been mentioned in Chapter III. It was found on the 
east coast of Florida in lat. 27° 30' N. 279 days afterwards, and 
therefore farther north than the two bottles above referred to, 
and like them it had been carried through the Florida Strait. The 
distance as determined by the U.S. Hydrographic Office is 3320 
miles, and the rate about twelve miles a day. From the foregoing 
data it may be fairly assumed that an average daily rate of seventeen 
miles between the Amazon coasts and the shores of Florida is not 
an excessive estimate for bottle-drift. Taking the distance at 3200 
miles, it would be covered in 188 days or about six months. 

Doubtless the track taken by these bottles across the Caribbean 
Sea and the Gulf of Mexico was also followed by a bottle, already 



446 



APPENDIX 



referred to, which reached the Florida keys from the St. Paul's 
Rocks area, travelling at a rate of not less than 18*4 miles a day. 

Note 2 (p. 10). 
The local beach-drift of the Turks Islands, 

The beach-drift derived from strand plants growing on the Turks 
Islands is often disguised by the mass of the foreign drift. But in 
the islands where there are mangrove swamps, as on Grand Turk, 
the germinating fruits and seedlings of the trees composing them, 
Rhizophora mangle, Avicennia nitida, and Laguncularia racemosa, 
are not infrequently thrown up on the beaches on the weather coasts. 
Although it is safest to assume that most of thern are of local origin, 
some of the seedlings of Rhizophora mangle that I observed had all 
the appearance of having been long afloat ; and it is likely that they 
came with the foreign drift. Several of the stranded Rhizophora 
seedlings, which had been more or less covered over with the Sargasso 
weed that is heaped up in quantities on these beaches, had established 
themselves firmly in the sand by rootlets three or four inches long. 

The larger local drift other than that derived from the mangroves 
is represented by the fruits of Coccoloba uvifera. However, much 
of the local beach-drift is made up of the small seeds and seed vessels 
of plants growing in the vicinity, such as Ipomcea pes-capro3, Sccevola 
plumieri, Suriana maritima, Tournefortia gnaphalodes, etc. This 
fine drift is sometimes sifted out by the waves and deposited higher 
up the beach away from the heavier large foreign drift, where it is 
generally associated with small rounded pumice pebbles 5 to 12 mm. 
across. 

Note 3 (p. 278). 

The effects of wind-pressure on some of the shrubs of the more 
exposed cays of the Turks Islands. 

These effects are well exhibited in the two small wind-swept 
islands of Pear Cay and Eastern Cay on the weather or eastern 
borders of the group. The trade winds seem to blow home with 
greater force on the weather cays, and it is here that the frequent 
gales and the occasional hurricanes seem to expend much of their 
repressive influence on the vegetation. The adaptive habit of growth 
is strikingly shown in the cases of Corchorus hirsutus, Suriana mari- 
tima, and Tournefortia gnaphalodes. They all at first bend prone 
with the wind, the trunks and prostrate branches rooting in the sand, 
held down firmly by rootlets several inches long, the subsequent 
behaviour varying in the different plants. 

In the case of Corchorus hirsutus the plant was prostrate along its 
entire length, its leafy branches spreading out like a fan on the sand 
and rooting freely and firmly, the whole measuring from ten to fifteen 
feet instead of three or four feet, the usual height of the erect indi- 
vidual. In such wind-swept stations it made no effort to assume the 
upright position. On the other hand, with the shrubs of Tournefortia 
and Suriana the erect habit ultimately asserted itself, the leafy 



APPENDIX 



447 



branches rising into the air and concealing the original prostrate 
growth. With Tournefortia gnaphalodes the main trunk branched 
low down close to the ground, the primary branches lying prone 
for a distance of two and a half or three feet and rooting firmly in 
the sand; whilst from them sprang the secondary branches, which, 
lying prostrate at first, finally arose erect and developed leafy stems 
two or three feet in height. With Suriana maritima the secondary 
leafy branches were upright and three or four feet high; but the 
main stem and primary branches for a distance of two and a half or 
three feet were prone and firmly held by their rootlets in the sandy 
soil. 

Note 4 (p. 188). 

On the experiments of Prof. Ch. Martins on the effects of sea-water 
immersion on the fruits of Cakile maritima (Bull. Soc. Botanique 
de France, tome IV., p. 324 : Paris, 1857). 

These experiments were made on the seeds and fruits of a large 
number of plants with the object of determining the persistence 
of the germinative capacity after long immersion in the sea ; but, as 
I point out in my book on Plant Dispersal (p. 539), an objection 
previously made by Thuret and Hemsley (Ibid.), the investigator often 
leaves us in doubt, when speaking of the floating capacities, whether 
he is referring to the initial or to the sustained buoyancy. His 
remarks on some of the fruits, including those of Cakile maritima, 
might lead one to suppose that germination occurred after forty- 
five days' flotation in sea- water ; but it may be that only immersion 
is implied, since he placed in the same category the fruits of Beta 
vulgaris, Eryngium maritimum, Pancratium maritimum, Ricinus 
communis, Salsola kali, etc., which, according to the observations 
of Thuret and myself, sink in a few days. Lloyd Praeger places the 
limit for Salsola kali at five and a half days (see Note 17). 

Note 5 (p. 227). 

On the synonymy of Sccevola plumieri, Vahl, and Sccevola 
kcenigii, Vahl. 

Before making the acquaintance of Sccevola plumieri in the West 
Indies I was led by the occasional application of the name Sc. lobelia 
to both plants to infer that they were forms of one species ; and Sc. 
kcenigii was therefore credited in my book on Plant Dispersal with 
a distribution over the tropics of the globe. Schimper in his Indo- 
malayische Strandflora (p. 130) was led into a similar error, since he 
states that Sc. plumieri is distributed over most tropical and sub- 
tropical coasts of both hemispheres. 

The exceedingly puzzling synonymy has been in recent years 
made clear in the monograph of the Goodeniacece by Krause (Das 
Pftanzenreich, IV., 277, 1912). The two plants, as was evident 
to me when I first met Sc. plumieri in the West Indies, are quite 
distinct, and could not be mistaken by any one with both before him. 
The German author, who refers them to different subgroups of the 



448 



APPENDIX 



genus, points out (p. 18) that the confusion of the two species has 
frequently given rise to very inaccurate accounts of their distribution. 
The difficulty seems to have arisen in connection with the early 
use of the specific name of lobelia as imposed by Linnaeus. Krause 
in re-examining the whole question must have experienced some 
difficulty in the process of selection, and it is not surprising that there 
is an omission here and there. Thus I found Sc. kcenigii to be in 
1888 a characteristic plant of Keeling Atoll, where it had been pre- 
viously collected by Darwin in 1836, the list of his plants being deter- 
mined by Henslow (Ann. Nat. Hist., I., 337, 1838; Chall. Bot, IV., 
113; Journ. Vict. Inst. London, 1889). 

Note 6 (p. 407). 

The strand plants of Teneriffe and of the north-east corner of Grand 

Canary. 

I examined the strand vegetation at various places on the coast 
of Teneriffe, namely, between S. Juan de la Rambla and Orotava, 
at Punta Hidalgo and in its vicinity, at Taganana and Armasiga, 
between Santa Crux and S. Andres, and to the south of Santa Cruz. 
The shore was mostly rock-bound, the beaches being generally few 
and scanty, so that the littoral plants as a rule were those that find 
their home on coastal rocks and on sea-cliffs as well as on the beaches. 
However, the beach flora was well developed on the sandy isthmus 
connecting La Isleta with the north-east corner of Grand Canary. 
But a much more extended acquaintance with the group would 
be required before one could venture to discuss the shore flora of 
the Canary Islands as a whole. Here there is merely offered a con- 
tribution to the subject from the standpoint of dispersal. 

In addition to several plants familiar on our English beaches, 
such as Atriplex portulacoides, Beta maritima, Crithmum maritimum, 
Euphorbia par alias, etc., there were a number of others, that either 
do not extend north of Southern Europe and the Mediterranean 
region or are confined to this and other Atlantic archipelagos (Azores, 
Cape Verde Islands), such as Frankenia ericifolia, F. pulverulenta, 
Mesembryanthemum crystallinum, M. nodiflorum, Zygophyllum, etc. 
Then there was the local element, which we should expect to find 
in all strand floras where the inland plants come down to the coast. 
Thus in places those strange-looking shrubs, the cactoid Euphorbia 
(E. canariensis) and Plocama pendula, which so often give a character 
to the barren hill-slopes of basic tuffs and lavas that descend steeply 
to the sea-border, come down to the coastal rocks, where they associate 
with typical shore plants like Crithmum maritimum and Zygophyllum. 

Amongst other strand plants of Teneriffe may be mentioned a 
Statice and a stout fleshy yellow umbellifer unknown to me. Both 
grow on the coastal rocks and ascend the precipitous lava slopes for 
100 or 200 feet or more. The umbellifer is remarkable on account 
of the greenish-yellow hue of the whole plant, its leaves being deeply 
cut into three cuneate lobes indented on their upper border. I 
may remark that in addition to the ordinary form of Crithmum mari- 



APPENDIX 



449> 



timum, where the separate carpels are about 6 mm. long and about 
4 mm. broad, there is a variety with longer and relatively narrower 
fruits (9 or 10 mm. long, 4 mm. broad), which seems to be confined 
to lava rocks at the coast, and does not like the usual form grow 
also on the beach. 

The locality in which I found the strand flora most developed 
was on the west side of the low sandy isthmus which connects La 
Isleta with the north-east corner of Grand Canary. Euphorbia 
par alias was the most frequent of the beach plants and extended 
inland for some hundreds of yards over the dunes. Amongst other 
plants growing on the sandy shore were Atriplex poiiulacoides, 
Frankenia, Heliotropium, Mesembryanthemum crystallinum, M. 
nodiflorum, Zygophyllum, etc. The last named also grew along the 
upper drift line where the beach was shingly and on the rocks border- 
ing the beach at La Isleta. 

A few remarks on the modes of dispersal of some of these plants 
may here be made. We cannot exclude human agency in the case 
of the two species of Mesembryanthemum, which were extensively 
cultivated in the group in the eighteenth century for the extraction of 
soda, according to Samler Brown's Guide to the Canary Islands (1905,. 
d, 9). These two plants grow also on the Salvages (Lowe's Florulas' 
Salvagicce Tentamen, 1869), and were employed in making barilla, 
(soda) by men engaged in the trade, who often visited the islands for 
that purpose (Ibid.). The dispersal of the carpels of Crithmum 
maritimum across the sea by the currents and locally by the winds 
is discussed in my book on Plant Dispersal (p. 542). It is there 
remarked that they are very buoyant and can float for several 
months in sea-water. They are so light that a strong wind blows 
them along the beach and up the faces of the sea-cliffs. (More 
recent experiments showed that the carpels in some cases germin- 
ated after floating for thirteen months in sea-water.) 

I experimented on the fruits of a species of Zygophyllum that 
nourished on the beach of the low isthmus connecting La Isleta 
with the north-east corner of Grand Canary. It is probably Z. 
fontanesii, a littoral plant found also in the Cape Verde Group (Schmidt 
and Coutinho) and on the Atlantic coast of Morocco (Hooker, p. 339). 
From the results of the experiments below given it may be inferred 
that the species tested has but a limited capacity for dispersal by 
currents. It might, however, accomplish a sea-passage of from 
100 to 200 miles. This would be quite sufficient for its derivation 
in the case of the Canary Islands from the neighbouring African 
coast and for its distribution over that group. 

The dry cocci of this species of Zygophyllum are 7 to 8 mm. long. 
They possess a solitary crustaceous seed (2-5 mm. in length) in the 
midst of spongy air-bearing tissue, and are so light in weight that 
like the carpels of Crithmum maritimum they are blown about on 
the beach by the winds. They would have possessed similar great 
floating powers, did they not tend to gape at the inner angle. As 
it is, the sea-water soon penetrates through the opening, and in 
consequence they float for only eight or ten days. The seed itself 
sinks. 



450 



APPENDIX 



From experiments made on the fruits of Atriplex portulacoides 
growing at Salcombe in South Devon (see Note 38 of the Appendix), 
it was evident that whilst the seed-like fruit sinks it can float when 
surrounded by the perianth between two and four weeks, buoyed up 
doubtless by air-bubbles. It thus might easily have been carried 
iby the sea to the Canary Islands from the adjacent continental 
-coasts. On the other hand, in the case of Beta maritima, which occurs 
■in Madeira and in the Azores as well as in the Canaries, the direct 
: action of the currents must be excluded, since the buoyancy of the 
fruit is limited to a day or two (Plant Dispersal, p. 542). Three 
other of the shore plants of this group, Euphorbia paralias and the 
two species of Frankenia, may here be noticed from the standpoint 
of dispersal. The seeds of the first named float for a long time 
unharmed in sea- water (Ibid., p. 543) ; whilst the very small seeds of 
Frankenia are probably distributed by birds. 

Note 7a (p. 10). 
The plant-stocking of islets in the Florida Sea, 

One of the most methodical series of observations on the stocking 
of islets in coral-reef regions with plants are those made by Mr. 
Lansing (junior) in 1904 on the sand-keys of Florida to the westward 
of Key West. He had been commissioned by the Field Columbian 
Museum of Chicago to carry out this inquiry. He collected speci- 
mens of everything he saw, noting carefully the plant arrangement 
in each islet, and laying down his results on maps made on the spot. 
His collections, together with his comprehensive notes and maps, 
supplied materials for a detailed consideration of the flora of these 
islets in a paper by Dr. Millspaugh published by the Museum in 1907. 
" As was to be expected " (to quote from this paper), " this archi- 
pelago proves to be vegetated with only the usual broad strand 
species common to similar situations on the Antillean islands in 
general." In discussing the results Dr. Millspaugh brought to bear 
an experience derived from a wide field of study of insular and 
strand formations in the Antillean region. The value of this paper 
for us lies in its illustrating the process of plant-stocking in the case 
of newly formed low islets in the West Indies. 

These sand-keys vary greatly in size, the smaller being usually 
from thirty to a hundred yards long, whilst the larger may measure 
.a mile or more. Their elevation is generally two to four feet ; but it 
may be as low as one foot and as high as nine feet. Of the nineteen 
keys examined only three exceeded four feet. The numerous small 
.keys, consisting exclusively of mangrove colonies, are not specially 
*dealt with in this paper. They, however, represent the earliest stage 
iin the plant- stocking process. My remarks here will be mainly 
(restricted to a consideration of these results from the standpoint 
supplied by my observations and experiments on the coral islets of 
the Indian and Pacific Oceans, as well as by those on the small cays 
of the Turks Group in the West Indies. In so doing I shall as a rule 
be following Dr. Millspaugh's guidance, though in my own fashion. 



APPENDIX 



451 



Different stages in the process are readily distinguished. It 
begins with the partial emergence of a bank of coral sand, which 
under the influence of the currents gradually acquires a more or less 
curved or crescentic form, its convexity facing the currents. For 
convenience we will take a medium-sized key and will designate the 
convex side of the bank as its weather margin. Whilst the bank is 
still washed over by the seas in places, various floating seeds and 
fruits, as well as seedlings, are cast up on its surface, those of the 
mangroves, more particularly the seedlings of Rhizophora mangle, 
establishing themselves under the shelter of the bank on its lee side. 
Islets may remain in the condition of a mangrove colony for some 
time. But as the exposed surface increases in extent typical beach 
plants begin to establish themselves. The seeds of some are brought 
by sea-fowl; but, as will be shown later on, the currents probably 
do most of the work. One of the first to establish themselves on the 
bank on the weather side is Sesuvium portulacastrum, and it is this 
plant that Dr. Millspaugh places at the head of his list illustrating 
the sequence of appearance of the most characteristic beach plants 
on these keys. This is followed in the order fixed by this authority 
by Cakile fusiformis, Euphorbia buccifolia, Cenchrus tribuloides, 
Cyperus brunneus, JJniola paniculata, Andropogon glomeratus, 
Suriana maritima, Tournefortia gnaphalodes, Borrichia arborescens, 
Iva imbricata, and Ambrosia hispida (A. crithmifolia). 

Two strand plants not sufficiently frequent on these keys to be 
included in the most representative plants, but amongst the first to 
establish themselves through the aid of the currents, not only on 
West Indian beaches, but also on new islets in the Indian and Pacific 
Oceans, are Canavalia obtusifolia and Ipomcea pes-capraz. Their 
place in the above list would be with the plants immediately following 
Sesuvium portulacastrum. Another of the early plants would be 
Sccevola plumieri, though it only grows on a few of the keys. 

By the time that the sandy surface is well stocked with beach 
plants the mangrove colony on the concave side of the bank has 
increased extensively, and we notice that though in great mass of 
Rhizophora mangle, two other mangroves, namely, Avicennia nitida 
and Laguncularia racemosa, have established themselves on the 
border facing the sandbank, where they are associated with Cono- 
carpus erectus. The mud-flat in the neutral zone between the beach 
plants and the mangroves is ultimately occupied by Salicornia 
ambigua, Balis maritima, and Sesuvium portulacastrum. 

We now approach the completed stage in the history of such a 
key, a condition which it is likely to preserve, provided man does 
not intervene, as long as the present relation between land and 
water prevails. Be the islet small or large, a limit to its growth at 
the borders is reached in the deeper water, both on the weather side, 
where the waves cease to heap up the sand, and on the lee side, 
where the Rhizophora colony no longer extends seaward. Through 
the reclaiming agency of the mangrove, the area of the swamp is 
much reduced and the beach plants advance on the new surface. 
The islet loses its crescentic form, and in the final stage it is mainly 
appropriated by the beach plants, amongst which Suriana maritima 



452 



APPENDIX 



often predominates in the interior with shrubs like Tournefortia 
gnaphalodes on its weather border, and beyond them, reaching to 
the wash-line of the sea, Euphorbia buxifolia, Cakile fusiformis, 
Sesuvium portulacastrum, Ipomcea pes-caprce, etc. 

In those cases where the original sand-keys lie close together and 
are only separated by shallow channels the mangroves lead to their 
ultimate union. Cases are cited in this paper where two keys, 
separated at the time the islets were charted by the U.S. Hydro- 
graphic Survey, were found by Mr. Lansing to be joined together. 
Writing of the Marquesas Group of these Florida sand-keys, Dr. 
Millspaugh says that through the growth of the mangroves and the 
upwashing of the light coral sand by the waves all the keys will in 
course of time unite to form a solid island embracing the whole 
group. It is, however, instructive to note that this growth of islands, 
whether singly or in combination, takes place under the conditions 
of the present sea-level. We get no indication in this paper of the 
formation of the seolian sandstone which has so long puzzled the 
geologist both in the Bermudas and in the Bahamas. The con- 
ditions for its development are not presented in the history of these 
Florida sand-keys. 

With reference to the means of dispersal through which these 
keys received their plants, Dr. Millspaugh holds that the balance is 
on the side of the bird, and he appeals mainly to the medium of the 
feet of sea-birds. However, I have endeavoured to adjust our views 
in the remarks made below on the probable mode of dispersal of the 
nineteen plants he names as most typical of these keys, to which I 
have added four which deserve a place in this treatment of the 
subject of dispersal, namely, Ipomcea tuba (= Calonyction album), 
Ipomoea pes-caprce, Canavalia obtusifolia, and Sccevola plumieri. A 
grouping of the plants according to their probable mode of reaching 
the Florida sand-keys is here presented. For particulars reference 
should be made to other pages of this work, to my book on Plant 
Dispersal, to my paper on Keeling Atoll, and to Dr. Millspaugh' s 
paper. 

(A) Plants brought by the currents, the seeds, fruits, seedlings, etc., 
being able to float long enough to reach these sand-keys : Avicennia 
nitida, Batis maritima, Cakile fusiformis, Canavalia obtusifolia, 
Conocarpus erectus, Ipomcea pes-caprce, Ipomoea tuba, Laguncularia 
racemosa, Bhizophora mangle, Salicornia ambigua, Suriana maritima, 
Tournefortia gnaphalodes. 

(B) Plants brought by currents and frugivorous birds : Sccevola 
plumieri. 

(C) Plants brought through the adherence of their fruits to birds' 
plumage : Cenchrus tribuloides, Euphorbia buxifolia (Millspaugh's 
authority). 

(D) Plants with small seed-like fruits that possess sufficient float- 
ing power to enable them to be brought by currents from neighbour- 
ing coasts, but which could also have been transported in the crevices 
of drifting logs : Ambrosia crithmifolia, Borrichia arborescens. 

(E) Plants with small seeds or seed-like fruits, all non-buoyant, 



APPENDIX 



453 



brought by drifting logs or attached to the feet of sea-birds : Cyperus 
brunneus, Dondia linearis, Iva imbricata, Sesuvium portulacastrum. 

(F) Plants, like Uniola paniculata and Andropogon glomeratus, 
that may have been brought, as Millspaugh suggests, by currents 
(Uniola), or through the agency of birds (Andropogon), but concerning 
which observation is needed. 

Only the most characteristic plants are here dealt with. Quite 
half of the twenty-three plants above named would owe their pres- 
ence on the Florida sand-keys to the direct agency of currents. In 
the case of a quarter, the agency of the drifting log could be appealed 
to. Though one may be too much inclined to fall back on the 
drifting log in cases of difficulty, its intervention is much more than 
a mere possibility. On Keeling Atoll I found a stranded log honey- 
combed by the Teredo, the empty burrows of which were filled by 
sand, with which many of the small pyrenes of Tourneforfia argentea 
and other small seeds were mixed. With a high tide and a heavy 
sea this log could have been swept off the beach and carried seaward. 
Birds might have aided in the case of the remainder. Frugivorous 
birds probably played a small part, since, if we except Sccercola 
plumieri, but few of the plants would possess fruits that would 
attract them. However, the plant just named was more probably 
brought by currents. But one or two of the plants not named in 
the list, such as Ernodea litoralis, might have been brought here in 
this way. Dr. Millspaugh informed me that the seeds of Euphorbia 
buxifolia become adhesive when moistened. So it has been placed 
in the group with Cenchrus tribuloides. The attachment of the 
prickly fruits of Cenchrus to one's clothes will be familiar to all who 
have sojourned in the tropics, one of the American names of the 
species above named being " claw-grass." 

Of the plants in the first group some would be dispersed through 
the floating seedling, as in the case of the species of Rhizophora and 
Azicennia. and also of Bat is and Salicornia, though with the last two 
plants the seeds (Batis) and the detached seed-bearing joints (Sali- 
cornia) possess independent buoyancy. The dispersal by currents 
of Salicornia peruviana, S. herbacea, Batis marituna, etc., is dealt 
with in my work on Plant Dispersal. 



Note 7b (p. 5). 

A comparison of the vegetation of sand-islets in the coral-reef regions 
of the West Indies, and of the Pacific and Indian Oceans. 

For this purpose the results of Mr. Lansing's observations on the 
Florida sand-keys will be utilised, as given in Dr. Millspaugh' s 
paper. Although the present writer has no acquaintance with the 
Florida sand-keys, he formed a close acquaintance with nearly all 
their characteristic plants on the shores of the Turks Islands. On 
Keeling Atoll and on North Keeling Island, on the south coasts of 
Java, in the Solomon Islands, and in Fiji, he became familiar with 



454 



APPENDIX 



the plants with which currents and birds stock the newly formed 
islets thrown up on the reefs of those seas. His first study in the 
plant- stocking process of such islets was made in the Solomon 
Islands in 1882-3, the particulars of which are given in his work on 
those islands and in the Appendix of Mr. Hemsley's volume on the 
botany of the Challenger expedition. Although the following remarks 
mainly apply to the region of the Western Pacific, it might in most 
respects apply to islets in the Indian Ocean, such as are presented on 
Keeling Atoll and in the small island of North Keeling to the north 
of it, many of the plants being the same. 

There are some points of similarity as well as great points of con- 
trast between the vegetation of reef-islets in the Western Pacific and 
in the Florida seas. In appearance there is a great contrast, since 
the large trees, often with handsome flowers and large fruits (Barring- 
tonia speciosa, Calophyllum inophyllum, Cerbera odollam, Guettarda 
speciosa, Hernandia peltata, Ochrosia, Pandanus, etc.), that line the 
beach in a Pacific islet are not to be found on islets in West Indian 
waters, where the vegetation bordering the beach is formed of shrubs 
and small trees of a very different character. Then, again, we miss 
in the Florida sand-keys the tall trees of Canarium, Eugenia, and 
Ficus (banyans) that occur in the interior of islets in the Western 
Pacific — islets only a few hundred yards in length and heaped up but 
two or three feet above the waves. These trees represent the work 
of the fruit-pigeons, an agency ever in operation in these seas. 

The similarity is greatest in the case of the plants creeping on the 
sand, and with the shrubs and small trees with their climbers that 
form the outposts of the beach vegetation. Canavalia obtusifolia, 
Ipomoea pes-caprce, Sesuvium portulacastrum, and Suriana maritima 
occur alike on the Florida sand-keys and on the coral islets of the 
Indian and Pacific Oceans. But representative species of the same 
genus may play the same role in the different regions. On the 
Florida sand-keys and in the Turks Islands bushes of Sccevola plumieri 
and Tournefortia gnaphalodes give the same character to the sand- 
dunes bordering the beach that is displayed by Scazvola koenigii and 
Tournefortia argentea on Keeling Atoll and in the islets of the Western 
Pacific. 

The differences also extend to the composition of the mangrove 
colonies formed on the lee side of the islets. Of the three mangroves, 
Rhizophora mangle, Avicennia nitida, and Laguncularia racemosa, on 
a Florida sand-key, only the first might be found in the Pacific islet, 
though its place would more probably be taken by the Asiatic species, 
Rhizophora mucronata. The species of Laguncularia would be repre- 
sented in the Pacific by a species of Lumnitzera, an allied genus. The 
genus Avicennia would not be present. 

If we except the agency of the fruit-pigeon in the Western Pacific, 
the currents would seem to be more effective in that region than in 
the Florida seas. Practically all the large trees lining the beach in 
the Pacific islets owe their presence there to the currents, whilst the 
fruit-pigeon has stocked the interior. 



APPENDIX 



455 



Note 8 (p. 131). 
The lake of the Grand Etang in Grenada. 

Situated in the centre of the island at an elevation of 1800 feet, 
this lake is 500 or 600 yards in length, and, as I ascertained by sound- 
ing in February 1909, rather under three fathoms in maximum 
depth. Since its depth is placed at fourteen feet in the eleventh, 
volume of the Encyclopaedia Britannica (ninth edition), a volume 
issued in 1880, it is apparent that there has not been much change 
in depth in a period of at least thirty years. Exaggerated notions 
prevail with regard to the depth, size, and even altitude of this 
mountain lake. Although it shallowness has long been known, I 
came upon, during my sojourn in the island, many coloured people 
who believed it to be unfathomable. Its circumference would 
measure barely a mile, yet the lake has been described as over two 
miles round and " no less than 3200 feet above the sea " (Stanford's 
Compend. Geogr., A. Keane, West Indies, 1901, p. 409). 

Its aquatic and subaquatic vegetation calls for a few remarks. 
Whilst a water-lily (Nymphaea ampla) occupies the shallows, a dense 
swampy belt of tall sedges, chiefly Cladium jamaicense, forms the 
borders. Arborescent aroids (Montrichardia arborescens), five or six 
feet in height, spring up in the midst of the Cladium belt, which is 
fringed at the water's edge by an equisetum-like Scirpus (either planta- 
gineus or constrictus). Sclerias of more than one species grow in 
abundance among the low trees at the border of the lake; and 
clambering over the branches of these trees Dioclea reflexa is fre- 
quently to be observed, with occasionally a Mucuna that comes near 
M. altissima, DC, as described in Grisebach's pages. [Specimens of 
the Cladium from this locality in the herbarium of the Botanic 
Garden in Grenada are named CI. jamaicense, Cr., on the authority 
of Prof. Urban. In the same collection the Nymph&a from the same 
lake is named N. ampla, DC] 

It is considered by Prof. Harrison that the lake of the Grand 
Etang probably occupies the place of a former crater. Its shallow 
depth, however, is not in favour of this view. If an accurate survey 
of the upland region of the island were made it would show that this 
shallow lake occupies the expanded head of a valley open to the 
north; and as far as the surface configuration is concerned I doubt 
if it would be at all suggestive of a crateral origin. I would imagine 
that the denuding agencies have re-shaped the central mountainous 
portion of the island to such an extent that the present valleys and 
mountain profiles have little or no relation with those of the era of 
volcanic activity. 

The overflow water is carried away by an effluent on the north 
side, which, according to the level of the lake, varies between seven 
and fourteen feet in breadth and between ten and thirty inches in 
depth. If this channel was deepened to the extent of twelve or four- 
teen feet the lake would be emptied. During heavy rains the level 
of c : lake will rise a foot in the course of a night. Thus during one 
nk sit of my sojourn, when 2*60 inches of rain fell at the rest-house 



456 



APPENDIX 



near by, the lake's level rose eleven inches. On account of the large 
amount of sediment that must be carried into the basin by the 
numerous small streams and rivulets that empty into it, the lake is 
evidently gradually filling up. Most of these materials are deposited 
in the basin, and I should fancy that in a few centuries the lake will 
have disappeared. This result will be brought about not merely 
through the silting process in the basin, but through the deepening 
of the channel of the effluent by its own erosion. 

During three days in the middle of February, when the tempera- 
ture of the air in the shade at the lake-side ranged between 65*5° 
and 73*0° F., that of the water of the lake's surface ranged from 
71*8° to 73-7° F., and that of the effluent 71 5° to 72'8° F. 

Note 9 (pp. 13, 87, 92). 

Guilandina bonduc and other species. 

Guilandina bonduc, though fairly well distributed, is not nearly so 
common in the West Indies as G. bonducella. Though both are 
littoral species, G. bonduc seems to be the species that is most at 
home inland. But the questions raised by these two plants, that 
often travel around the tropics of the world together, are much 
more complex in the New World than in most other regions. Yet 
even in the Pacific islands, as I have shown in my work on Plant 
Dispersal, they give rise to several difficulties; but the tendency to 
differentiation that they there display is much more marked in the 
American continent, and there is ground for the belief that the two 
types will admit of being broken up into several smaller specific or 
subspecific groups. Urban in his Symbolce Antillance (II., 270-6), 
though he does not separate them from the Csesalpinias, describes 
eight or nine peculiar West Indian species of the Guilandina type, 
usually with yellow or orange-coloured seeds, and mostly from Cuba. 
But island groups like the Bahamas, and even the Caymans, may 
possess their own peculiar forms, and Millspaugh has described a 
new shore species from the last-named locality that stands nearest 
to G. bonducella (Plantar Utowanai). 

My inference in the Pacific that seed-buoyancy in Guilandina 
goes with station rather than with species, plants of the beach 
having buoyant seeds and those from inland seeds that sink, would 
not seem to be of general application in the West Indies. Thus on 
the beaches of St. Croix I found Guilandina bonduc associated with 
G. bonducella, but only the last had buoyant seeds. Indeed, my 
data seem to indicate that in the West Indies seed-buoyancy in 
Guilandina goes with species rather than with station. When in 
Grenada I tested the buoyancy of the seeds of G. melanosperma, a 
variety of G. bonduc with black seeds, from Antigua; but they all 
sank in sea- water. The lack of buoyancy of the seeds of this species 
in the West Indies may be predicated from their rarity in beach- 
drift. An indication in the same direction for the genus is afforded 
by the fact that in the case of an inland species, apparently un- 
described, that I found in the woods on the lower slopes of Mount 



APPENDIX 



457 



Diablo in the heart of Jamaica and 1500 or 1600 feet above the sea, 
33 per cent, of the seeds floated in sea-water. All these facts and 
inferences for Guilandina in the West Indies invite further inquiry 
into the relation between seed-buoyancy and station. Guilandina 
bonducella, true to its behaviour in the tropics of the Old World, 
possesses typically buoyant seeds. The difficulty of connecting a 
littoral station with seed-buoyancy is concerned with G. bonduc and 
the inland species of the genus. 

A few remarks on the station of Guilandina bonduc in the West 
Indies may here be added. Sloane, writing of the plants of Jamaica 
in the latter part of the seventeenth century (Nat. Hist. Jam., II., 
41), states that the Nicker plant with yellow seeds (G. bonduc) grew 
everywhere in the Jamaican savannahs. I found it associated with 
G. bonducella on the beaches of St. Croix; and the two species are 
characteristic littoral plants in the Virgin Islands (Harshberger, 
Phyt. N. Amer., p. 686). It grows, according to Grisebach, on the 
sandy seashore of Antigua. 

I raised some young plants of perhaps an undescribed species 
from chocolate-brown Guilandina seeds gathered from amongst the 
Orinoco drift washed up on the south coast of Trinidad. The seeds 
are ovoid but rather compressed, and measure 27 x 20 x 14 mm., 
and float buoyantly. The plants, when eight inches high, had 
prickly stems. The leaflets, in three or four pairs, were three to 
four inches long, lanceolate or ovato-lanceolate, with a rounded, 
rather oblique base, and a long tapering aristate apex. 

The species, above mentioned as growing as a stout climber in 
young wood 1500 or 1600 feet above the sea on Mount Diablo in 
Jamaica, may perhaps be one of Urban' s Cuban species. It was 
neither in flower nor in fruit, the seeds (yellow, oblong, 23 x 15 mm.) 
of the previous season lying on the ground. The leaflets, in five or 
six pairs, were two to three inches long, oblong or obovate, rounded 
or subcordate at the slightly oblique base, with usually a tapering 
apex terminating in a hair-line point. No stipules observed. 

Note 10 (p. 122). 

Mucuna pruriens, DC. 

The use of the name Mucuna pruriens, DC, as applied to a species 
with large globoid seeds, an inch across, which occur in West Indian 
beach- drift and are washed up on the shores of Europe, has led to 
some confusion. It is not clear how the confusion arose; but two 
species have been thus confounded, M. pruriens, DC, an annual and 
a weed of cultivation which has been spread by man all around the 
tropics, and M. urens, DC, a stout-stemmed, woody climber that 
grows on high trees at the borders of forests in the New and in the 
Old World and is found also at the coast. The first is known as the 
Cow-itch plant, and, as I observed in the West Indies, is common in 
land once cultivated, as in abandoned sugar-cane fields. The plant 
is a great nuisance when the pods dry and the covering of stinging 
hairs comes off. In Tobago it was credited with keeping Indian 



458 



APPENDIX 



coolies out of the island. The second is known in the West and 
East Indies as the Horse-eye and Donkey-eye plant, from the peculiar 
appearance of the seeds. Its pods have also a covering of stinging 
hairs ; but, as the writer knows from a personal experience of both 
plants, the irritation produced from this cause is much less than 
with the Cow-itch. 

It is not often that we can recognise the confusion between the 
two species as clearly as we can in the case of a reference to Mucuna 
pruriens in the System of Botany, by Le Maout and Decaisne (Engl, 
edit., 1873, p. 373). We there read that it is an Indian annual called 
Cow-itch, the seed being " called Donkey's Eye, from the large, 
pupil-like areola of the testa." Here we have the true M. pruriens 
credited with the seeds of M. urens, the seeds of the two species 
being, as will be shown below, utterly different in appearance. An 
«rror in the reverse direction is sometimes found. Thus Hillebrand, 
in his book on the flora of the Hawaiian Islands, after describing the 
true M. mens observes that it is " well known as the Cow- itch plant " 
and is a native of the West Indies and of tropical America. The 
true M. pruriens, which is a pest both for man and beast in old 
clearings and abandoned cultivations, is the plant, it may be here 
repeated, that is known as Cow-itch. 

In his Report on the Botany of the Challenger Expedition (I., 43; 
IV., 141, 277, 299) Hemsley applies the name of Mucuna pruriens, 
DC, to the Mucuna seeds found in West Indian beach-drift and 
washed up on the coasts of Europe. The seed which at the end of 
the seventeenth century Sloane recognised amongst the stranded 
seeds (Molucca beans) of the Orkney Islands as the " Horse-eye 
bean " familiar to him in Jamaica (Phil Trans., XIX., 398, 1695-7) 
is identified in this report (IV., 277) as M. pruriens. The two species 
are there mentioned under the name of M. pruriens, DC, on 
different pages. In the one case, we have a plant " commonly 
cultivated and now almost cosmopolitan in the tropics" (IV., 141). 
In the other case, it is a plant the seeds of which were found by 
Morris in Jamaican beach-drift, and they are described as " some- 
times washed ashore on the western coast of Europe " (IV., 299). 
As is remarked below, the seeds of M. pruriens proper do not occur 
in beach-drift and possess no floating powers. 

Yet as a result of the confusion, which probably dates back to the 
early part of last century, botanists must have often experienced the 
same difficulties. For instance, Ernst in his account of the new 
flora of Krakatau (1908, pp. 36, 37, 41, 46) mentions M. pruriens 
DC, as amongst the new vegetation that has established itself since 
the great eruption on the coasts of the neighbouring island of Ver- 
laten, where it climbs on the strand trees. Schimper makes no 
reference to such a species in his work on the Indo-Malayan strand 
flora, and we can only conjecture that it was not the annual species, 
the weed of cultivation, to which this specific name was originally 
applied. 

It would seem that botanists have been misled by the lack of any 
description of the seed of Mucuna pruriens in the works most acces- 
sible to them, De Candolle's Prodromus (tome II., 1825) and Grise- 



APPENDIX 



459 



bach's Flora of the British West Indian Islands (1864). Yet, as 
pointed out by Sagot, when writing in the Bulletin de la Societe 
Botanique de France in 1875 (XXII., 292), the seed was very accu- 
rately described by Jacquin in his work on American plants in the 
middle of the eighteenth century. It was also described and figured 
by Bentham a hundred years after in the Flora Brasiliensis of 
Martius (Vol. XV., part 1, p. 169, tab. 46, 1859-62). Both these 
works are quoted by Grisebach in connection with the plant, and his 
lack of reference to the seed seems unaccountable. Perhaps the 
reason may lie in the same doubt that first suggested itself to Sagot ; 
that is to say, whether two plants, like M. mens and M. pruriens, 
that are associated in the same genus by their floral characters, 
would possess seeds so different. Grisebach, with Jacquin' s and 
Bentham' s volumes by his side, says nothing of the seed of either 
species. 

The difference in appearance between the large, globoid, iron-grey 
seeds of Mucuna urens and the small, sub-reniform, mottled brown, 
shining seeds of M. pruriens is well brought out in Bentham' s figures. 
The first are thick-shelled, an inch across, and nearly surrounded by 
the black raphe. The second, which the present writer compares 
with ordinary Phaseolus seeds and Sagot with small haricots, are 
relatively thin-shelled, barely half an inch in length, and possess a 
large scar but no circular raphe. The seeds of M. urens, again, 
possess great buoyancy. Those of M. pruriens, as my experiments 
indicate, possess none. The first are distributed unharmed by the 
ocean currents. The second have evidently been dispersed by man 
along trade routes. The first are characteristic of beach-drift in the 
West Indies and elsewhere. The second have never been recorded 
from beach-drift, nor are they at all likely to occur there. 

For a long while I clung to the use of the name of Mucuna pruriens 
as applied to a species with seeds of the M. urens type, since its 
employment was backed by high authorities. However, when I 
included seeds of this type under the name in a collection of West 
Indian drift sent to the Natural History Museum in 1912, Dr. Rendle 
kindly pointed out that they were not those of M. pruriens, which 
were much smaller and more oblong in form, and that they were 
probably those of M. urens. This decided the matter. In the 
treatment of the drift seeds of Mucuna in other parts of this work 
it is pointed out that there are two kinds of seeds of the urens type 
dispersed by currents; and the specific name of " pruriens " was in 
the above-named collection applied by me to the seeds which are 
now designated in these pages as 44 near urens," seeds that may be 
those of M. altissima, DC, a matter discussed on p. 120. 

Note 11 (p. 60). 

The relation between the floras of Ascension and St. Helena and the 

currents. 

As we learn from Hemsley (Chall. Bot., III., 32-4), we have no 
positive proof that more than two of the flowering plants of Ascen- 



460 



APPENDIX 



sion are really indigenous, namely, Hedyotis adscensionis and Euphorbia 
origanoides, both of which are endemic. The first is more nearly 
related to African and Asiatic species than it is to the St. Helena, 
H. arborea. The second has its nearest ally in E. trinervia from the 
Guinea coast, there being no indigenous species of Euphorbia in 
St. Helena. Current-borne seeds could only reach Ascension through 
the agency of the Main Equatorial Current, which would carry drift 
to it from tropical Africa and from the extra-tropical southern 
part of the continent, the South African Current here coming into 
play. 

St. Helena, lying as it does in the track of the South Equatorial 
Current, which is fed by the off-shore waters of the South African 
Current, would not receive any African drift except from the southern 
extremity of the continent ; but through the intermediate agency of 
the South Atlantic Connecting Current it would be the recipient of 
drift from the South American region gathered by the Brazil Current 
between Cape St. Roque and the River Plate. It would be quite 
cut off by the currents from Ascension and could receive no drift 
from the north, Dr. White's contention that the flora and fauna 
arrived from the north in the direction of the Cape Verde Islands 
being quite untenable (quoted by Scharff, p. 388). If the currents 
have been concerned in stocking the island, they would have brought 
to it seeds from South Brazil and the River Plate as well as from 
the Cape. It is noteworthy that whilst Hooker finds the most 
characteristic affinities of the flora in southern extra-tropical Africa, 
Hemsley, following Bentham, points to equal or closer affinities 
between its arboreous Composite and South American types (Ibid., 
III., 59). 

Though there is no evidence that the plants concerned are dis- 
tributed by the currents, it is remarkable that this agency, if effec- 
tive, might possibly explain in both Ascension and St. Helena the 
affinities determined by the botanists. Yet from the endemism of 
the genera with South American affinities, it may be inferred in the 
case of St. Helena that whilst the South American connection is 
largely a thing of the past, that with South Africa has been main- 
tained up to relatively recent times. (The system of currents pre- 
vailing in the South Atlantic is discussed in Chapter III. and Note 18.) 

Note 12 (pp. 51-55). 

Bottle-drift on the Azores. 

The answer to the question as to the source of the vegetable drift 
stranded on the Azores is plainly given in the results tabulated below 
for bottle-drift. All the seeds stranded there must come from the 
west, namely, from the coasts of the New World between Newfound- 
land and the West Indies. Nothing comes from the eastward, and 
it will subsequently be shown that bottles dropped into the sea in 
the vicinity of this group either display the same easterly drift or are 
carried south into the North Equatorial Current, ultimately reaching 
the West Indies. This conclusion applies to all seasons of the year, 



APPENDIX 



461 



the lack of data in the American charts for the summer months 
being supplied in Schott's memoir. 

All of the twenty-seven bottles dealt with in this table came from 
the region between Sable Island off the Nova Scotian coast and 
Cuba, but the number for each locality is no indication of relative 
frequency, since most of the experiments were begun in the north. 
It is noteworthy that none of these bottles approach the group from 
the southward, all from the quarter between West and North-north- 
west — a fact brought out in the cases of those dropped into the sea in 
mid-ocean to the westward of the islands. To the southward and 
westward lies a debateable region from which, according to the 
compiler of the American charts, but few bottles are ever recovered, 
though " crossed by numerous sailing and steamship routes and 
within which in all probability are cast as many bottle papers as in 
other portions of the ocean." This region lies between the main 
drifts of the Gulf Stream and North Equatorial Current, and, accord- 
ing to the same authority, is confined between 25° and 40° N. lat. 
and 30° and 60° W. long. But even if we curtail these limits a little, 
since bottles can reach the Azores from the same parallel a few 
hundred miles to the west, the fact remains that in this part of the 
central Atlantic there is interposed between the Azores and the 
New World to the south-west the vast area of the Sargasso Sea, 
covering some 120,000 square miles, where, as Laughton (p. 221) 
observes, collects a very large proportion of the drift or wreckage 
which floats about the Atlantic. This may explain why four and even 
six years may elapse before some of the bottles are recovered on the 
Azores. Indeed, the progress of drift to the Azores seems to be 
never rapid. Of the rates given for nineteen bottles not one reaches 
ten miles a day. Though those drifted there from the vicinity of 
Cape Hatteras seem to travel at the same speed as those that are 
carried to Europe from the same locality, the passage from the 
Nova Scotian region is very tedious, bottles taking rather longer for 
the drift from that region than they do from Cape Hatteras, although 
the distance is much less. 

The fate of other bottles thrown into the sea in the vicinity of the 
Azores, between 60 and 150 miles east and west of the group, is 
illustrated in Dr. Schott's paper. Of four, one was recovered on the 
coast of Norway, and the others, after being carried south, were 
transported by the North Equatorial Current to the West Indies, 
being found on the Bahamas, on one of the northern islands of the 
Lesser x4.ntilles, and on the north-west coast of Cuba. 

It would seem, therefore, that whilst the islands of the Azores can 
only receive drift from the coasts of North America and from the 
West Indies, they can supply it to the coasts of Europe and to the 
West Indian region. 

The Prince of Monaco's observations in 1885 and 1887 to the 
N.N.W. and N.W. of the Azores at distances of 200 to 800 miles, 
largely confirm the results above given, in the case of bottles thrown 
overboard 200 to 750 miles W. and N.N.W. of the group. Of eleven 
floats that reached there from distances between 280 and 460 miles 
N.N.W. of the islands, the three most rapid drifts gives a mean of 



462 



APPENDIX 



6*9 miles a day (7*7, 7*3, 5*7). Of twenty-six floats thrown over be- 
tween the Azores and the Great Bank of Newfoundland, the five 
most rapid drifts give a mean daily rate of 5*3 miles. 

Table Illustrating the Localities from which Bottle-drift 
reaches the azores 

(The averages for the time occupied in the drift and for the daily rate are estimated 
from the shortest periods elapsing between the dates of the start and recovery of the 
bottle, as given in the last column. Most of the data are from the American charts, 
the remainder are from Schott's memoir, but all the daily rates are based on the 
former, the details of the references being given on p. 47). 





dumber 

of 
Bottles 


Distance 


Averages 


Shortest 
Drifts in Miles 
per Day 


Starting-place 


in 

Nautical 
Miles 


Days 


Miles per 
Day 


South of Cape Sable and Sable 
Island between 38° and 43° N. 
lat 


8 


1500 


294 


5-1 


5-6; 4-5 (A) 


Off Cape Hatteras within a 
radius of 300 or 350 miles 


8 


2400 


273 


8-8 


9-9; 7-7 (B) 


Off the E. coast of Florida . . 


1 










Off the N.W. coast of Cuba 


1 


3180 


435 


7-3 




To the westward of the Azores, 
200-750 miles W.-N.N.W. . 


9 


400 


71 


5-6 


6-4; 4-8 (C) 




27 






- 





(A) Drift-rates for 6 bottles. 



Note 13 (pp. 56-58). 
Bottle-drift in the Turks Islands. 

The Turks Islands, with the neighbouring Caicos Islands and the 
two Inaguas, have received a large amount of bottle-drift. We 
learn from the Rev. J. H. Pusey's Handbook (1897) of these islands 
that bottles are " constantly being picked up by the natives." 
During my sojourn in the Turks Group in 1911 I found that the 
coloured people had lost their interest in returning the enclosed 
records, since no money was forthcoming. Fortunately plenty of 
material is at my disposal for determining the directions from which 
bottle-drift reaches this region, and also the direction it takes when 
it passes the islands to places beyond. Below will be found data for 
thirty-three bottles which were recovered in these islands, and for 
forty bottles which were dropped into the sea in the middle of the 
channel between the Turks Islands and the Hispaniola coast. 

We see there that three bottles reached here from the vicinity of 
the Azores; one from off the south-west of Ireland; one from off 



APPENDIX 



463 



Lisbon; fourteen from the region included in the Madeira, Canary, 
and Cape Verde Groups; two from mid- Atlantic to the eastward; 
eight from a few hundred miles N.-E.N.E. of the Turks Islands; 
three from between Bermuda and the Bahamas; and one from off 
Cape Hatteras. But this list of localities should be supplemented 
from the data supplied by bottles that passed between the Turks, 
Caicos, and Inagua Islands and were recovered on the Bahamas 
farther west, as well as on the north coast of Cuba. The Bahamian 
islands receive bottle-drift not only from the localities above named, 
but also from the eastern side of the Lesser Antilles and from the 
shores of the Guianas and North Brazil. The Antillean Current, 
referred to in Chapter III., would be instrumental in this direction, 
and a good instance is there mentioned of a bottle which was stranded 
in the middle Bahamas after being thrown into the Main Equatorial 
Current between St. Paul's Rocks and Cape St. Roque. 

All the bottles that reach the south-eastern Bahamas from the 
eastern side of the North Atlantic have followed the track of the 
North Equatorial Current to the West Indies; and where, as often 
happens, they have started as far south as the Cape Verde Islands, 
they cross the Atlantic well south of the 20th parallel and arrive at 
the Turks Group after brushing the coasts of the northern islands of 
the Lesser Antilles. A glance at the map will show that in the last 
case the drift approaches the Turks Islands from E.S.E., and that 
these islands receive the drift which in the Antillean Current has 
traversed the Lesser Antilles between Porto Rico and Guadeloupe. 
The tracks of several bottles, as laid down in the American charts, 
directly indicate that much drift from the south-east, which would 
otherwise have arrived at the south-eastern end of the Bahamas, 
has been intercepted by Porto Rico, the Virgin Islands, St. Thomas, 
and other islands in that region. 

Just as suggestive of the prevailing direction taken by drift, when 
traversing the south-eastern Bahamas, are the results given a page 
or two later for a large number of bottles dropped into the sea between 
the Turks Islands and Hispaniola. Out of forty all were carried to 
the westward, and nearly all entered the passage between Cuba and 
the Bahamas leading to the Florida Strait. Though most of them 
were stranded on the way, usually on the Cuban side, three passed 
through and reached the straits. Of these, two got no farther and 
were beached on the coast of Cuba; but one was caught in the 
swift current of the Gulf Stream, and after a drift across the Atlantic 
was recovered 337 days afterwards on the west coast of Ireland. 
This westward trend of the bottle-drift after passing between 
the Turks Islands and Hispaniola is the effect of the Antillean 
Stream. 

The conclusion to be drawn from all these bottle-drift data is very 
significant of the direction of the drift traversing the south-eastern 
Bahamas. There is a prevailing set in a W.N.W. direction towards 
the Florida Strait; but although much of the drift is stranded on 
the way a certain proportion reaches the straits, and some of it gets 
within the influence of the Gulf Stream. The indications are, there- 
fore, that the Turks Islands lie in the track of drift on its way in the 



464 



APPENDIX 



Antillean Stream to the Florida Strait from regions to the eastward 
and southward. 

But in the winter months, when the North-east Trade blows freshest 
and is often very northerly, these islands are also the recipient of 
drift from the northward and eastward, probably mostly material 
that would otherwise have passed to the eastward of the Turks 
Group, but is thrown back on the beaches by the strong " northers " 
that are not infrequent in this season. During the winter bottle- 
drift may even arrive at these islands from the vicinity of Bermuda. 
Dr. Schott (p. 13) in this connection observes that the N.W. direction 
of the drift in the seas between the Bahamian and Bermudian Islands 
is not always illustrated by the bottle -drift, and he gives a case where 
a bottle thrown over early in February about 150 miles S.S.W. of 
the Bermudas was recovered on the Turks Group forty-nine days 
later, the distance covered being 542 miles. 

I will first give the data concerning bottles stranded on the islands 
forming the south-eastern extremity of the Bahamas, namely, the 
Turks and Caicos Islands and the two Inaguas. They are mainly 
supplied in the American charts and in Dr. Schott's paper; but a 
few are taken from the Nautical Magazine for 1852. The following 
is a grouping of the materials according to their starting-places. 



Sources of bottle-drift found on the south-eastern islands of the 

Bahamas, 

A. Vicinity of the Azores within a radius of 400 

miles 

B. Off the south-west coast of Ireland, 260 

miles distant 

C. Off the coast of Portugal, near Lisbon, 50 

miles from land 

D. In the vicinity of Madeira and the Canary 

Islands within a radius of 160 miles . 

E. About 120 miles off Cape Blanco and half- 

way between the Canary and Cape Verde 
Islands 

F. In the vicinity of the Cape Verde Islands 

within a radius of 250 miles to the north, 
south, and west 

G. In mid-ocean, 1000 to 1500 miles E.-E.S.E. 

of the Turks Islands 

H. Between 100 and 350 miles N.-E.N.E. of 

the Turks Islands between December and 
March 

I. Between Bermuda and the Bahamas during 

January and February 

J. Off Cape Hatteras 



3 bottles (9 %) 

1 » (3 %) 

1 » (3 %) 

6 (18 %) 

1 „ (3 %) 

7 „ (21 %) 

2 „ (6 %) 

8 „ (25 %) 

3 „ (9 %) 
1 „ (3 %) 



33 „ (100 %) 



APPENDIX 



465 



The above list, as already implied, does not exhaust the sources 
of the bottle-drift stranded on the south-eastern Bahamas. On 
the islands of the same group, farther to the north-west, have been 
recovered bottles dropped into the sea off the east side of the Lesser 
Antilles and off the coasts of the Guianas and of North Brazil, 
which, as they were borne along in the Antillean Stream, must have 
passed between the Turks, Caicos, and Inagua Islands, to reach their 
destinations. 

The subjoined notes refer to the results above given : — 

A. The average distance by Madeira and the Cape Verde Islands 
route would be about 4200 miles, the greatest daily rate indicated 
being 7-2 miles. 

B. Recovered after 597 days, giving a minimum daily rate of 8-5 
miles over a distance of 5100 miles (see Note 20). 

C. D, E, F. Except in two cases only the tracks on the chart are given. 
In one of them a belated drift of only 3-5 miles a day was indicated. 
In the other, which is given in Purdy's Columbian Navigator for 
1839, a bottle from off Madeira was found ten years afterwards 
on the Turks Islands. 

G. The fastest daily rate up to the time of recovery was 5-S 
miles. 

H, I. All were stranded during the winter months, a season when 
the Trade may blow strongly for long spells from the north. The 
number of bottles thrown over a few hundred miles to the northward 
and eastward give an excessive idea of the relative frequency of 
drift from this quarter, since the captains of one or two ships seem 
to have been especially interested in this point. At this season, 
also, drift may arrive from the vicinity of the Bermudas. 

J. Recovered after 309 days. It probably accomplished a short 
circuit of the North Atlantic by being deflected south in the neigh- 
bourhood of the Azores. Several bottles thrown over at the same 
time reached the shores of Europe (see p. 49). 

Equally suggestive, as significant of the direction pursued by 
floating drift in this region, are the indications of bottles dropped 
overboard in the seas between the south-eastern Bahamas and His- 
paniola. In the American charts are given the data for forty bottles 
thrown over between October and May just half-way between the 
Turks Islands and the coast of Hispaniola in or about 20° 30' N. and 
71° 30' W., and about forty miles S.S.W. of the Turks Group. They 
were mostly cast over from the S.S. New York in 1906; but some 
were thrown over from the S.S. Cherokee in 1905, besides one or 
two from other vessels. There was evidently a special reason for 
selecting this locality, which on account of the number of bottles 
thrown over there, probably some hundreds, if we allow for the non- 
recoveries, must be nearly un ique in the West Indian region. Doubt- 
less it was concerned with the investigation of the Antillean Stream, 
which is the current that traverses this region on its way northward 
and westward towards the Florida Strait. The results of these 
experiments are now given. 

H H 



466 



APPENDIX 



^Places of recovery of forty bottles cast overboard about half-way 
between the Turks Islands and the adjacent coast of Hispaniola. 

A. North coast of Cuba 29 bottles 

B. Middle and north-west Bahamas . . . 7 „ 

C. Jamaica and the Cayman Islands . . 2 ,, 

D. Yucatan 1 „ 

TL Ireland 1 „ 

40 

A. Most of them were stranded on the north-east coasts of Cuba, 
but two or three were carried farther and thrown ashore on the Cuban 
side of the Florida Straits. The average daily drift rate indicated 
was not over eight or nine miles. 

B. The average drift was five or six miles a day. 

D. Stranded on or near Cozumel Island : daily drift 9-6 miles. 

E. Recovered on the coast of County Mayo 337 days afterwards, 
giving a daily drift rate over 4140 miles of 12-3 miles (see Note 20). 



Note 14 (p. 49-54). 
The bottle-drift of the Bermudas. 

(Materials mainly supplied by the American charts, but also by the papers of 
X)r. Schott and the Prince of Monaco.) 

As regards its relation to the circulatory system of currents in 
the North Atlantic, Bermuda may be viewed as situated near the 
inner end of an eccentric spiral, of which the outer end may be 
considered as represented by the Gulf Stream, as it rushes through 
the Florida Strait, and the terminal portion as represented by 
the Antillean Stream curving northward and eastward from the 
region dividing it from the Bahamas. On the face of things, there- 
fore, we should expect that these islands would receive much and 
impart but little. 

I have at my disposal the records of about forty bottles, recovered 
on these islands, which ought to supply sufficient materials for a 
preliminary inquiry into the subject; but it will be necessary to 
make at first a brief reference to the implications involved in such 
an investigation. As regards the Bermudian fauna and flora opinion 
seems to fluctuate between two schools of thought : the older school 
typified in the views of Wallace, Hemsley, and others, who consider 
that the islands have been stocked through the agencies of birds and 
currents, and the newer school typified in the views of Dr. Scharff 
and others, who see in the Bermudian indigenous plants and animals 
the remains of an ancient fauna and flora which this region received 
when joined to the North American continent ( Scharff' s Distribution 
and Origin of Life in America, pp. 183-95). 

As far as the starting-places indicate, bottle-drift may reach the 
Bermudas from all points of the compass. Bottles have arrived there 



APPENDIX 



467 



from off the Nova Scotian coast due north of the group (one) ; from 
between the Azores and the Great Bank of Newfoundland (three) ; from 
the Eastern Atlantic opposite the Bay of Biscay in about longitude 18° 
W. (two) ; from the Eastern Atlantic in the latitude of the Canary 
Islands, but about 800 miles further west (one) ; from mid- Atlantic 
between the parallels of 20°-23° N. and the meridians of 40°-50 / W., 
within the northern border of the North Equatorial Current (three) ; 
from Florida coasts and from Cuban seas (three); from off the 
continental coasts to the westward in the region of Cape Hatteras 
(fifteen); and from a number of directions all around the group 
in the case of bottles dropped overboard in the vicinity. The possibi- 
lities of Bermuda as a gathering-place for drift are great when we 
regard the area of the region indicated by the starting-places of the 
bottles that have been thrown up on its shores. Such a region 
would comprise the breadth of the North Atlantic from coast to 
coast between the 20th and 50th parallels of latitude. Although 
the possible starting-place might lie anywhere at the borders of this 
region, the point of approach would be nearly always from the west, 
the range varying usually between north-west and south-west. 

This brings one to remark that the Bermudas occupy a singular 
position with regard to the two principal currents that could supply 
them with drift — the Gulf Stream from the New World and the North 
Equatorial Current from the old World. It receives what is played 
off from the borders of one current and what is brought to it by a 
connecting stream from the other. 

As regards the Gulf Stream, it receives the " tailings " of the current 
as it proceeds northward to Cape Hatteras and is gradually deflected 
eastward towards Europe. This is well shown when we compare 
the daily rates of bottle-drift reaching Bermuda from the Cape 
Hatteras region with those for bottles reaching Europe from the same 
locality. Thrown overboard within a radius of 250 or 300 miles 
from Cape Hatteras, which would include the main stream of the 
current, bottles are carried to Europe, a passage of over 3000 miles, 
at an average rate of eight to nine miles a day, whilst the passage 
of 500 or 600 miles to Bermuda is accomplished at an average rate 
of rather over five miles a day. The American charts supply data 
for fifteen bottles that reached Bermuda from the Hatteras region. 
The quickest minimum rate of 5-4 miles a day was attained in two 
cases, whilst the three bottles next in speed gave rates of 5-3, 5-3, 
and 5-1 miles. The consistency in the five fastest rates enable one to 
largely eliminate the effects of delay in the recovery of the bottles. 
The contrast between the slow drifting rate to Bermuda and the fast 
drifting rate to Europe is well illustrated by a set of five bottles that 
were thrown over together from the S.S. Cherokee about a hundred 
miles north of Cape Hatteras, the particulars of which are given 
in Chapter III. Two bottles recovered on the Bermudas gave 
minimum daily rates of 3-1 and five miles, whilst those picked up on 
the Scottish coast, on the Shetlands, and near the North Cape of 
Norway, gave minimum rates of 7-8, 6-9, and 10-2 miles respectively. 
The playing off of drift from the outer border of the Gulf Stream 
towards the Bermudas is probably continued as the current heads 



468 



APPENDIX 



towards Nova Scotia after passing Hatteras. That the process 
begins soon after the current emerges from the Florida Strait is 
indicated below. 

West Indian vegetable-drift, as is well known, is thrown up on 
the Bermudas in quantity; but the indications of bottle-drift are 
that it would be usually belated. Vegetable-drift reaching the 
islands from this region would hail from the seas between South 
Florida, Cuba, and the Bahamas and from the coasts around. In 
most cases, however, there would seem to be great delay, and it 
is evident from the behaviour of bottle- drift that it may be carried 
around the North Atlantic before it is stranded on the Bermudian 
coasts. There is the case of a bottle that was recovered in Bermuda 
nearly three and a half years after it had been dropped into the 
sea, in February 1902, between Key West and the Cuban coast 
(Amer. chart, Febr. 1909). There is another case of a bottle that 
after being dropped over near Key West, in October 1901, was picked 
up on Bermuda five and three-quarter years afterwards (Amer. 
chart, Oct. 1908). Then we have a bottle which was found on Ber- 
muda 466 days after it had been cast into the sea about 200 miles 
to the northward of Great Abaco (N.W. Bahamas), though the direct 
passage across the sea was barely 600 miles (Amer. chart, Febr. 
1909). But that the passage of West Indian drift to these islands 
may at times be fairly rapid is illustrated by a bottle that was re- 
covered in Bermuda seventy-three days after it had been cast over- 
board in the northern part of the Florida Strait, the passage of 900 
miles having been accomplished at a minimum daily rate of rather 
over twelve miles (Amer. chart, Nov. 1908). The behaviour of 
this bottle indicates that the tailing off of drift from the Gulf Stream 
towards Bermuda may begin soon after the current issues from the 
Florida Strait. 

From the data above given, as far as they go, it may be inferred that 
West Indian seed-drift may reach the Bermudas in the following 
ways. It may be deflected eastward from the Gulf Stream soon 
after the current issues from the Florida Strait, when the passage 
would occupy two or three months. This deflection may not take 
place until the current passes Cape Hatteras, when the time occupied 
would be five or six months. The drift may be carried past the 
Bermudas in the Gulf Stream and accomplish the circuit of the 
North Atlantic, returning in the North Equatorial Current, which 
would cover three years. Drift from the north-west Bahamas would 
probably only reach Bermuda by getting within the influence of 
the Gulf Stream farther north, a tedious process that is illustrated 
by one of the bottles. 

With the North Equatorial Current, the carrier of drift from the 
Old World, the Bermudas are connected by means of the Antillean 
Stream (see Chapter III.), as is explained by Schott (p. 13). But 
probably they would only receive in this way the drift in the slack 
waters of the North Equatorial Current north of the 20th parallel. 
In the American chart (May 1909) the track is given of a bottle, 
thrown over in mid- Atlantic" in lat. 22° 54' N. and long. 39° 42' W., 
which accomplished a passage computed at 2430 miles at the mini- 



APPENDIX 



469 



mum rate of 7-8 miles a day. In the same charts, but for December 
1908, there is a track of a belated bottle which reached Bermuda 
from a position about 600 miles further west on the 22nd parallel. 
In both these cases allowance is made for the northward curve of 
the Antillean Stream towards Bermuda, which the bottles approach 
from the south-west. The same plan is followed by Schott in laying 
down the tracks of bottles reaching Bermuda after traversing the 
Atlantic in the North Equatorial Current, though he gives the 
Antillean curve a greater sweep and makes them approach the 
islands from the west. According to this chart one such bottle 
which was thrown into the sea about the 28th parallel and about 
800 miles west of the Canaries was picked up at sea nearly 200 miles 
N.E. of Bermuda. 

But two bottles have been stranded on these islands which were 
cast into the sea in the eastern Atlantic only 400 or 450 miles north- 
west of Cape Finisterre. On their way south in the Portuguese 
or North African Current they would pass near Madeira and the 
Canary Islands before coming within the influence of the North 
Equatorial Current, and the whole passage of about 4300 miles 
would probably occupy about two years. No details are given 
either by Dr. Schott or by the Prince of Monaco, from whose pages 
these two records are taken ; but from the data for similar traverses 
given in Chapter III. we should probably be not far wrong, if, after 
allowing for the delay in reaching and leaving the North Equatorial 
Current, we placed it at about six miles a day. In Dr. Schott' s 
example we can determine the approximate position of the starting- 
place (46° N. 19° W.) from his map; but in that of the Prince of 
Monaco we can only say that it was one of a large number of floats 
that were dropped over in 1886 along the 18th meridian of west 
longitude and between the parallels of 42° 30' and 50° N. 

Still more interesting are the records of three floats thrown over 
in the Prince of Monaco's observations of 1887 between the Azores 
and the Great Bank of Newfoundland, as well as to the north of 
that group. They form 2 per cent, of the recoveries, and taking 
the Prince's general estimate of such drifts at 6-4 miles a day, the 
passage of about 5000 miles implied would occupy about twenty-six 
months, and would almost involve the circuit of the North Atlantic 
by way of the Portuguese and North Equatorial Currents. An 
approach yet nearer to the completion of this circuit is concerned 
with a bottle thrown over about 130 miles to the south-east of Cape 
Sable (Nova Scotia) and recovered in Bermuda 1602 days afterwards. 
In the American chart (Dec. 1908) the passage is computed at 
5880 miles, which gives a minimum rate of only 3-7 miles a day, and 
the compiler characterises it as " almost completing the circuit 
of the ocean." It is noteworthy that although this bottle was 
cast over about 580 miles north of Bermuda, its passage to those 
islands involved a distance tenfold in amount. This well illustrates 
the peculiar position of Bermuda with regard to the currents of the 
North Atlantic. It is in the track of none of them, yet at the end 
of all of them. 

This brings one to notice another feature in the relation of these 



470 



APPENDIX 



islands to the North Atlantic currents. Whilst they may receive 
drift from all round this ocean, they do not figure often as distributors 
of drift to distant regions. The records of bottle-drift at my disposal 
for the North Atlantic number some hundreds; but there is only 
one record of any distant region having received drift from the 
vicinity of the Bermudas. They give nothing to the adjacent 
coasts of America only a few hundred miles away. Bottles thrown 
into the sea within a day's steaming from their shores usually find 
their way back to the islands sooner or later, even if years elapse. 
I have the records of seven bottles dropped in the seas around 
Bermuda, to the north, south-east, south-west, west, and north-west, 
at distances ranging between 200 and 350 miles. Five out of them 
were recovered on the islands ; but only in one case is a rapid passage 
indicated; and here a bottle was recovered twenty-five days after 
it had been dropped overboard about 300 miles to the south-east 
of the group. Of the other four, one from 240 miles to the north 
was found seven months afterwards ; another from 300 miles W.N.W. 
was picked up also after seven months; another from 350 miles to 
the west was recovered after nearly six months; and the last from 
200 miles to the south-west was not found on the islands until two 
years had passed. It does not, therefore, seem easy for drift to 
leave the Bermudas, since at most if it obtained an offing it would 
be caught in the baffling play of the currents around the islands and 
would be returned after an interval perhaps of months or years. 
The behaviour of bottle-drift in Bermudian waters was evidently 
a source of difficulty with Schott, who remarks (p. 13) on the numerous 
examples from this region concerning which it is scarcely possible 
to determine their tracks. 

Yet under certain conditions it might be possible for the Bermudas 
to establish a connection with the Bahamas. But apparently it 
would be only in the winter months, when the North-east Trade 
blows freshest and blows home in these seas, that such a connection 
would be practicable — a matter mentioned in the treatment of the 
bottle-drift of the Turks Islands in Note 13. Schott (p. 13) gives 
an instance of a bottle, which, dropped over about 150 miles S.S.W. 
of Bermuda, early in February, was picked up on the Turks Islands, 
at the extremity of the Bahamas, forty-nine days later. He quotes 
the ship's log to the effect that at the time of the start the conditions 
of wind and current were unfavourable for any drifting passage to the 
Turks Islands ; but with this exception we know nothing of the actual 
conditions experienced by the bottle in this remarkable drift. The 
possibility, however, of the passage of drift from Bermudian seas to the 
Bahamas is illustrated in the preceding note on the Turks Islands. 
It is there shown that many bottles reach the south-east Bahamas 
during the winter months from the northward and eastward, the 
longest drift being accomplished by bottles from within 300 miles 
of Bermuda. Here I may mention the tracks of five others, referred 
to in the American charts for the winter months from November 
to March, where the bottles reached San Domingo and the central 
and north-west Bahamas from about half-way between Bermuda 
and the Bahamas. 



APPENDIX 



471' 



Occasionally, again, a bottle breaks away altogether from the 
eddies of the Bermudian seas and reaches the opposite coasts of 
the Atlantic ; but it starts from the Gulf Stream side of the islands 
200 miles to the westward, and would represent the track not of 
Bermudian but of West Indian and American drift. Thus in the 
American chart for February 1909 the track is given of a bottle 
that was recovered on the Orkney Islands fourteen months after 
it had been thrown over about 200 miles W.N.W. of Bermuda, 

Viewing the group as the recipient rather than as the distributor- 
of drift, it is curious to notice how many localities on the opposite 
coasts of the North Atlantic would supply it with these materials. 
Though well outside the tropics, it figures as regards vegetation 
mainly as an outlier of tropical lands to the south and west. It is 
in that direction that we must chiefly look for results of effective 
dispersal by currents. The current that brings it seed-drift from 
that quarter would derive it from Cuban and Florida seas, as well 
as from the continental shores brushed by it as far north as Cape 
Hatteras ; but for the most part the Cuban and Florida drift would 
be alone effective. The currents that brought bottle-drift from s 
few hundred miles off Cape Finisterre sweep past the coasts of Morocco 
and the islands of Madeira and the Canaries, and would doubtless 
bring seed-drift from those localities, which, however, would be 
mostly ineffective for the purpose of dispersal, since a passage of 
one and a half and two years would be involved. Strange but 
useless gifts might arrive from the shores of Nova Scotia and New- 
foundland after a circuit of the North Atlantic covering about three 
years. 

The Bermudas would be practically cut off from South America 
and from the regions from which the Main Equatorial Current: 
derives its drift. I have no record of any bottle reaching these; 
islands from equatorial regions or from the South Atlantic. There> 
is, however, a possible connection through the Antillean Stream;; 
but the drift which that current supplies to Bermuda would be 
the drift it receives at its eastern border from the northern portion 
of the North Equatorial Current, and not the drift that its main 
stream at times brings to the Bahamas from the coasts and rivers 
of the Guianas and Brazil. Bottle-drift from the South American 
localities just named may, as we have seen in Chapter III., reach 
the Florida seas ; but I have found no record of its having ever been 
recovered on the Bermudas. Still, the possibility remains. 

Note 15 (p. 51). 

The circuit of the North Atlantic accomplished by drift. 

It would not be possible in the case of bottle-drift to be absolutely 
certain that one and the same bottle had accomplished this circuit, 
since evidence such as is supplied by derelicts of the position at 
different stages of the passage would not be forthcoming. The 
chances, however, of its having happened often are very great. 
Its antecedent possibility is proved over and over again in piece- 



472 



APPENDIX 



meal fashion in the bottle-drift charts. For instance, the traverse 
from the West Indies to the coasts of Europe by the Gulf Stream 
route and back again in the North Equatorial Current in tropical 
latitudes is there many times illustrated. Several bottles have 
performed the greater part of the circuit. Thus, one from the Cape 
Verde Islands which reached the coast of Ireland must have taken 
the West Indian route (see p. 59). Then, again, we get cases of this 
kind. Bottles have been found on the Turks Islands from off the 
Irish coast, and on the west coast of Ireland from the vicinity of the 
Turks Islands (Note 20) ; the route in the first case being by the Cape 
Verde Islands and the North Equatorial Current, and in the second 
by the Straits of Florida and the Gulf Stream. An assumption that 
the circuit of the North Atlantic has been almost accomplished is 
justified where bottles have been thrown over in the vicinity of the 
Nova Scotian coast and are found four years after on a Bermudian 
beach (see Note 14). 

The circulatory movement of the waters in the North Atlantic 
was established by the Prince of Monaco's extensive experiments, 
as discussed in Chapter III.; but since his field of observation did 
not extend to the western part of the ocean his conclusion was mainly 
based on the drifting of his floats from positions north-west and east 
of the Azores to the West Indies, the western portion of the circuit 
being assumed, according to common knowledge, to be the work 
of the Gulf Stream. The nearest approach to the completion of 
the circuit by a single float was displayed in three cases, where his 
floats thrown over to the north-west of the Azores were subsequently 
recovered on the Bermudas. 

The principal delay in the circuit of the North Atlantic would 
take place in the eastern portion of the ocean in the passage south 
from European waters to the zone of the North Equatorial Current 
in the vicinity of the Cape Verde Islands. This is indicated in the 
table in Chapter III. dealing with the drifting rates of bottles ; and 
it is well brought out in the circular drift of the derelict Alma 
Cummings from off Cape Hatteras to Panama, where drifting 
rates of sixteen or seventeen miles a day characterised the Atlantic 
traverses in the Gulf Stream and in the North Equatorial Current 
and a rate of only four miles a day in the passage of the intervening 
zone (Schott). The track of the Alma Cummings is described 
by Schott (p. 13, map 1) from materials given in the Nautical 
Magazine for 1896. Since its positions were fixed during its passage 
and the date of its beaching on the coast of the Panama Isthmus 
was known, the estimate that it accomplished a passage of 5320 
:miles at the average rate of ten miles a day is well founded. 



Note 16 (p. 50). 

Traverse of the North Atlantic by the derelict " W. L. White." 

An interesting record is supplied in the case of the derelict schooner 
W. L, White, which was drifted to the Hebrides from Baltimore 



APPENDIX 



473 



Bay (about 240 miles north of Cape Hatteras) in rather over ten 
months (315 days). Dr. Schott, who gives the data in his memoir 
(p. 10, map 1), obtained them from the supplementary pilot chart 
of the North Atlantic for February 1889 (U.S. Hydr. Office). From 
the several positions determined during its passage it is apparent 
that about five months were occupied in drifting about within an 
area a few hundred miles across to the eastward of Newfoundland. 
Had it not been for this interruption the traverse of the ocean would 
have been accomplished within six months. After the first two 
months the vessel was water-logged and was entirely under the 
influence of the current. In the first half of the traverse, before 
the decks were awash, the average daily rate was sixteen miles; 
but the last 550 miles were covered at ten miles a day. The general 
track of the derelict may be placed at about 3200 miles, which gives 
an average daily rate of ten miles on her course from Baltimore 
Bay (March 13, 1888) to the Hebrides (Jan. 23, 1889). 



Note 17 (p. 447) 
Mr. Lloyd Praegefs experiment on seed-buoyancy. 

In a paper entitled " The Buoyancy of the Seeds of some Britannic 
Plants," which was published in the Scientific Proceedings of the 
Royal Dublin Society for 1913, Mr. Lloyd Praeger gives the results 
of by far the most extensive series of experiments hitherto made 
in this inquiry. He gives his own results for 786 species of flowering 
plants, and supplementing them with those obtained by others 
for plants not experimented on by himself he supplies the data for 
just 900 British plants. I may be pardoned for adding that the 
results, to use the author's own words, fully bear out the conclusion 
formed by me as the outcome of an earlier series of experiments that 
" the buoyant-seeded plants in our flora are in the main inhabitants 
of either riverside or seashore " (p. 49). 

This investigator also improved on the methods of his predecessors 
as far as direct experiment is concerned. The discrepancies between 
his own results and mine may be due, as he remarks, partly to the 
variable behaviour of the plants themselves and partly to different 
conditions of experiment. Of the first kind he gives some striking 
examples. His results also support the conclusion first formed by 
Darwin, and confirmed by those who followed him, that the great 
majority of seeds possess little or no floating power, probably not 
less than 90 per cent. 

Unfortunately space does not allow me to do more here than to 
refer to these very important investigations; but I may remark 
that my results were also based on prolonged observations on the 
floating seed-drift of ponds and rivers. A combination of the two 
methods may remove some of the difficulties. Any young naturalist 
eager to take the subject up would find opened up for him a very 
interesting field of inquiry, and a very good guide in the paper of 
Mr. Lloyd Praeger. 



474 



APPENDIX 



Note 18 (p. 60). 

The differentiation of the Main and South Equatorial Currents in 

mid- Atlantic. 

I will here deal with the indications that in mid- Atlantic the Main 
Equatorial and South Equatorial Currents can be differentiated, 
and that they are separate but contiguous currents. They are 
afforded by six bottles that were dropped into the sea at different 
times in the vicinity of the island of Ascension, the data for which, 
supplied in five cases by Schott and in one case from the Nautical 
Magazine, are given in the table below. They were cast over in 
three cases on the north side of Ascension and in the other three 
on the south side at distances varying between 50 and 350 miles 
from the island. The southernmost, thrown over in 11° 38' S. 
lat., was stranded on the coast of North Brazil (2° 40' S. lat.) ; the 
others being recovered in three cases on Trinidad, one on the Grena- 
dines, and one on the south-east coast of Jamaica. All these bottles, 
even the southernmost, were borne along in the Main Equatorial 
Current, none of them being carried south of Cape St. Roque. The 
first three were solitary bottles that were thrown over in different 
months and different years. The last three were thrown over on 
three successive days from a ship proceeding north-west on the 
track between St. Helena and Ascension, and they require particular 
attention in this connection. 

The first thrown over about half-way between the two islands in 
lat, 11° 38' S. was stranded at Paranahiba on the north coast of 
Brazil in lat. 2° 40' S. The second starting from a position nearer 
Ascension in lat. 10° 4' S., reached the Grenadines in the Lesser 
Antilles in lat. 12° 42' N. The third cast over in lat. 8° 39' S. and 
about fifty miles south-east of Ascension was recovered near Morant 
Bay on the south-east coast of Jamaica in lat. 17° 56' N. The 
implication is that bottles thrown over in the Main Equatorial 
Current in the vicinity of Ascension reach the West Indies; whilst 
those thrown into the same current half-way between St. Helena 
and Ascension reach the coast of Brazil north of Cape St. Roque, 
which divides the Main and South Equatorial Currents. From this 
we should expect that if from the same ship bottles had been cast 
over near St. Helena they would have been carried south when 
approaching Cape St. Roque in the southern current. From this 
point of view Ascension would be regarded as within the zone of 
the Main Equatorial Current and St. Helena as in the track of the 
South Equatorial Current. 

This is what was meant by the differentiation of these two equatorial 
currents in mid-Atlantic, the drift of the main stream ultimately 
getting into the Guiana Current and that of the southern stream 
into the Brazilian Current. This distinction acquires importance 
when we come to consider the current connections of Ascension and 
St. Helena. From this standpoint they would be quite isolated 
as far as direct communication by currents is concerned. Such 
a view is supported by data supplied by a bottle which after being 



APPENDIX 



475 



thrown into the Indian Ocean off the coast of Natal was recovered 
at Alcobaco in Brazil in lat. 17° 30' S. It was held by Dr. Schott 
(pp. 19, 27, map 4) that the track of this bottle probably lay near 
St. Helena. Fuller details of this interesting drift have been given 
on p. 63. 



Data relating to Bottles thrown over in the vicinity of Ascension 
(7° 56' S. Lat. ; 14° 22' W. Long.) 





Starting-place 


Time when 


Place of 
Recovery 


No. 


Distance in 






S. 
Lat. 


W. 
Long. 


thrown over- 
board 


of 

days 


Miles and 
Daily Rate 


Remarks 


1 

2 


3° 30' 
6° 2' 


15° 0' 
15° 6' 


May 
January 


Trinidad 
Trinidad 


192 


3000 at 
15-6 per 
day 

4017 at 
18-1 per 
day 

3264 at 
11-7 per 


Schott, map 2, No. 
318; position ap- 
proximate 

Nautical Magazine, 
1852, No. 45 


3 
4 
5 


7° 30' 
8° 39' 
10° 4' 


13° 0' 
13° 50' 
11° 55' 


September 

February 23, 
1875 

[February 22, 
1875 


Trinidad 

Jamaica 
(Morant 
Bay) 
Grenadines 


222 
280 


Schott, map 3, No. 
333 ; position ap- 
proximate 
Schott, p. 27, map 
1, No. 302 

Schott, p. 27, map 
1, No. 301 


6 


11° 38' 


9° 5' 


February 21, 
1875 


Paranahiba, 
N. Brazil, 
lat. 2°40'S. 


175 


day 
1977 at 
11-3 per 
day 


Schott, p. 27, No. 3 



Note. — Nos. 6, 5, 4, were dropped over from the ship Schwan on three successive 
days. 



Note 19 (p. 59). 

The Guinea Current. 

In the region between 2° S. and 10° N. lat. and 20° and 32° W. long., 
where the Guinea Current flows east between the North and Main 
Equatorial Currents, lies an area of conflicting streams, a subject 
which is discussed in detail by Dr. Schott (p. 17). A bottle thrown 
over in its centre in May would be cast up on the coasts of Africa; 
whilst if dropped over in October it would be carried to the West 
Indies. The effect of the shifting boundaries of these currents is 
well illustrated in the vicinity of St. Paul's Rocks in the south-west 
corner of this region. Here in certain months of the year it would be 
difficult to predict whether the bottle would drift to the east or to 
the west. A striking example is supplied by Schott in the case of 
two bottles thrown overboard together on February 24, 1893, in 
lat. 1° 44' N. and long. 27° 16' W. (pp. 10, 18, map 1). One was 
recovered on the coast of Sierra Leone on September 8 of the same 
year, and the other on the Nicaraguan coast on March 8 of the following 
year. 

The Guinea Current must often carry back to the African coasts 



476 



APPENDIX 



drift that it has captured from the two equatorial currents. This 
would be especially the case, as pointed out by Schott (p. 17), with 
the drift of the southern current. But the important feature is 
that the Guinea Current during the northern summer extends much 
farther west than in winter. During a portion of the year this current 
is restricted mainly to the eastern half of the Atlantic ; but it may 
at other times extend to the vicinity of the South American and 
West Indian region and assume the role of a true counter-equatorial 
stream. The extension westward and the withdrawal eastward of 
this current greatly affects the drifting direction of bottles thrown 
overboard in the area above described. Schott carefully worked 
out this point, and from his results, elaborated on page 17 of 
his memoir, it appears that we have the real explanation why bottles 
dropped into the sea in this area at the same place in different seasons 
arrive in one case at the American and in another at the African side 
of the ocean. 

Whilst the varying behaviour of the bottles as indicated by Schott 
would limit the extension and retreat of the Guinea Current within 
the meridians 22° and 32° W., the actual extension westward may 
be much greater. We learn from the Admiralty publication (Africa 
Pilot, Part I., 1907, p. 49), that its western limit can be traced at 
all seasons of the year as far as the 23rd meridian (W. long.), but that 
in the summer and autumn months an easterly current extends as 
far west as the 53rd meridian. " This is probably " (as the writer 
proceeds to remark) " an expansion of the Guinea Current proper, 
or a counter-equatorial current." Laughton (p. 225) is representative 
of those who treat the counter-equatorial current as a thing apart 
from the Guinea current. It may be that the difference in view 
is only concerned with a difference in names. The Admiralty view 
that the first is a summer and autumn extension of the second is 
directly stated in Captain Jackson's Winds and Currents (p. 26, 
1904). 

It is in its character as a counter-equatorial stream that the Guinea 
Current attracts the interest of the student of the trans-oceanic 
distribution of seeds in this part of the Atlantic. We are wont to 
consider that through the agencies of the two equatorial streams 
Africa figures only as the giver and the West Indian and tropical 
American region as the recipient in the process of distribution of 
seeds by currents in these warm latitudes. But here we have pre- 
sented the possibility of a reversal of the operation, when Africa 
becomes the borrower from the New World. On account of the 
great predominance of the westerly drift currents in these seas the 
indications of the floating bottle would as a rule illustrate only 
the transference of drift from the African to the American side of the 
Atlantic. But occasionally the track of a bottle from the American 
to the African side breaks through this routine. Thus in Schott's 
first map there is the course laid down of a bottle (No. 425) which 
was recovered on the coast of Sierra Leone after being cast overboard 
in March about 270 miles N.E. of Cape St. Roque, and less than a 
hundred miles north of the island of Fernando Noronha, the approxi- 
mate position being in about 2° S. lat. and 32° W. long. Its track 



APPENDIX 



477 



has the appearance of lying athwart the stream of the South Equa- 
torial Current; but since the 32nd meridian in March represents 
the westerly limit from which, according to Schott's tabulated 
results (p. 17), bottle-drift reaches the African coast, we have here 
evidently the result of the extended Guinea Current acting as a 
true counter-current across the breadth of the Atlantic. At such a 
time the counter-stream might readily capture some of the vegetable 
drift washed off the coasts of North Brazil. 

There is thus a possibility that at certain seasons seeds may be 
transported from this part of the South American sea-border to 
the snores of Sierra Leone and Liberia. It is here that the South 
American and African continents make the nearest approach, only 
about 1550 miles separating Cape St. Roque from the nearest point 
of Africa. It is only a possibility, and, although the event may be 
of very rare occurrence, it cannot be ignored. 

Note 20 (p. 72). 

Bottle-drift from the South-east Bahama seas to the coast of Ireland 

and back. 

The following two bottles performed between them the circuit 
of the North Atlantic, the track of the first being by the Straits of 
Florida and the Gulf Stream route, that of the second by the North 
African and North Equatorial Currents. 

(a) Thrown over in April 1906, in the channel between the Turks 
Islands and the Haitian coast. Recovered 337 days afterwards 
on the west coast of Ireland (lat. 53° 45' N.), having covered 4140 
miles at the minimum rate of 12*3 miles a day (see Note 13). The 
details are given under Bottle 59 in the U.S. chart of the North 
Atlantic for May 1909. 

(h) Thrown over in January 1900, about 260 miles to the west 
of the south-west coast of Ireland in lat. 51° 15' N. and long. 17 a 
16' W. Recovered after 597 days on the Caicos Islands at the 
south-eastern end of the Bahamas, having covered 5100 miles at 
the minimum daily rate of 8*5 miles. The details are supplied in 
the U.S. chart of the North Atlantic for December 1908. 



Note 21 (p. 85). 

On some small-seeded West Indian littoral plants. 

Brief reference may here first be made to the group of four small- 
seeded littoral West Indian plants, Sesuvium portulacastrum, Portu- 
laca oleracea, Herpestis monniera, and Heliotr opium curassavicum, 
that are generally distributed in the tropical and subtropical regions 
of the globe — the two first being characteristic of the sandy beach, 
the third of marshy ground, and the last often of saline mud around 
lagoons. In all cases the seeds possess little or no buoyancy, and 
doubtless much of the cosmopolitan range of each of these plants 
is due to the agency of the drifting log bearing the seeds in its crevices, 



478 



APPENDIX 



to the unintentional assistance of aboriginal man in his long canoe 
voyages, and to birds. They came under my notice on almost every 
coast I visited in warm regions, whether insular or continental. To 
discuss the various interesting points raised by these plants would 
be to travel beyond the limits assigned to this work. Not the 
least important is the presence in some regions side by side with 
these cosmopolitan plants of peculiar species of the genus. Thus, 
both the Hawaiian and West Indian Islands have in each case 
peculiar species of Portulaca. That men and animals have been 
active factors in the dissemination of some of these plants in inland 
regions is very evident. Thus, Portulaca oleracea is not only a plant 
of the sandy beach, but it grows in waste ground away from the sea. 
There was a story told, I believe, by the late Sir Joseph Hooker, 
relating to a botanist, who, on landing on one of the uninhabited 
islands of the Southern Ocean that had never been explored, fell 
on the sand with his face in the midst of a patch of Portulaca oleracea. 

The above list could be much extended if we added plants not 
quite so widely spread. Thus, to take the case of Corchorus hirsutus, 
a typical West Indian shore shrub, also found on the east coast 
of Africa and in Australia. Its seeds are about 1*5 mm. in size, 
and the species owes its wide distribution over the warm regions 
of the globe doubtless to a variety of agencies human and otherwise. 
Then there are the salt-loving herbaceous plants that are widely 
distributed in the New World growing on the mud-flats bordering 
lagoons and coastal swamps, such as Salicornia ambigua and Balis 
maritima. Although, as is shown in my book on Plant Dispersal 
in the cases of other species of Salicornia and in that of Batis maritima, 
these plants are especially well fitted for dispersal by currents, 
since the seeds germinate in sea-water and the floating seedlings 
there thrive, it is obvious that considerations other than those 
concerning means of dispersal are here presented to us. Salicornia 
is a genus distributed over the greater part of the globe, and Batis, 
which holds only a single species, is restricted to the New World. 
Batis maritima has been recently introduced into the Hawaiian 
Islands, having been first found by Hillebrand in a small island off 
Honolulu in 1859, and no doubt its introduction was due to human 
agency. 

Note 22 (p. 343). 

The Azores and their African connections as illustrated by Sphagnum. 

One of the most useful features in Warnstorf's monograph on the 
Sphagnacece is a list of all the known species of Sphagnum grouped 
according to the floral regions. It often happens that the student 
of distribution has to make such a list for himself; but here he finds 
reference made easy; and the amount of time thus saved is very 
considerable. But the method has its disadvantages, since much 
explanatory material is needed to safeguard the student against 
pitfalls ; and perhaps it would be wisest in the absence of such matter 
to employ such a list with caution when drawing general inferences. 
A case in point is represented in this work. At the end of the list 



APPENDIX 



479 



of African species (p. 35) it is pointed out that the majority of them 
are endemic, the only exceptions being ten species that are there 
named. But unless the student goes through the whole list, there 
is nothing to indicate, what is actually the fact, that seven of these 
species are not known from the African continent at all, and only come 
into the list as components of the Sphagnum flora of the Azores, 
a group of islands placed here under Africa. All the seven species 
range widely over the globe, and their inclusion as African would 
thoroughly change the character of the Sphagnum flora of the con- 
tinent, especially as concerning its external connections, Africa 
being almost a closed region as far as the Peat-mosses are concerned. 
With respect to Sphagnum, the Azores are plainly a part of the 
European region, there being no African affinity, and no North 
American connections except such as are also European. 

Note 23 (p. 38). 

Pumice on the beaches of the Azores. 

Pumice is washed up in quantities on Azorean beaches, but 
doubtless it is almost all of local origin. On the north coast of San 
Miguel it is very abundant, being evidently brought down in the rainy 
season by streams from the inland districts. Pumice-tuffs often 
predominate in the interior, and as a result of their disintegration 
pumice is strewn over great areas of the surface. The pumice is 
evidently andesitic, being naturally darkish in colour but presenting 
a light-coloured, weathered exterior. The fragments are as a rule 
very buoyant when freshly removed from the tuffs, and no doubt 
would float for years. (In one of my experiments in the Solomon 
Islands, referred to in my book on the geology of that group, andesitic 
pumice pebbles originally gathered in the tow-net at sea remained 
afloat after two and three-quarter years.) In time, however, pumice 
lying exposed on the surface in wet localities loses its buoyancy. 
Thus I found that after being exposed for a long period on the scantily 
vegetated higher slopes of Pico da Vara in San Miguel, where the 
rainfall is great, the pumice fragments had become sodden and 
no longer floated. On the shores of Lake Furnas in the centre of 
the island they may be seen in a well-rounded state, due to attrition 
during prolonged flotation in its waters. In that state they are 
carried down by the effluent streams to the sea. It is therefore 
necessary to remember that pumice may begin its trans-oceanic 
voyage in a well-worn condition. 

Note 24 (p. 377). 

Trailing growth of Anagallis tenella. 

A singular variation in growth was displayed in an experiment 
made in South Devon some years ago. The typical plants are 
usually described as possessing creeping stems a few inches long 
(three or four inches). However, in the spring of 1906 I noticed 



480 



APPENDIX 



growing in a large pot containing a shrub some young plants of this 
species. I had been in the habit of mixing Sphagnum with soil 
for potting purposes, and evidently the plant had been introduced 
in this way in the previous autumn. As the soil-conditions were 
very much drier than those of the boggy ground in which the species 
normally grows, I resolved to note their effect on the young plants 
in question. 

During the summer of 1906 they developed a trailing habit, the 
main stems, seven inches long with secondary leafy shoots two inches 
in length, hanging over the sides of the pot. Through the winter 
they remained in the same leafy state, and in the spring rapid growth 
took place, so that by July 1907 the main stems were seventeen 
inches in length (three inches in the pot and fourteen inches hanging 
over), the secondary shoots or branches being proportionately long. 
Flowering now occurred, and the pot draped all around with the 
hanging stems formed quite a pretty spectacle. It remained thus 
until the autumn, when I went abroad and the experiment ended. 
The experiment was repeated in November 1912, when I put some 
other plants in an ordinary pot of soil and kept them in the same 
conditions as before. After flowering in midsummer the plants 
began to trail over the sides of the pot, producing stems about six 
inches long. When in the Azores, I watched carefully on the moors 
for evidence of this trailing habit, but only found a tendency in this 
direction in the case of plants growing in drier conditions on the sides 
of banks. 

The leaves in these experiments were much larger than with the 
typical growth, 7x6 mm. instead of 3 x 2*5 mm. The usual 
winter leaf of the normal plant is particularly small, 2 to 3 mm.; 
whilst the summer leaf is as a rule markedly larger; but I found 
that this is only indirectly due to the season. In November of two 
different years I noticed that the typical small leaves were produced 
when the plant lay flat on the oozy mud or on a level patch of boggy 
ground, which would be usual in winter. In places, however, where 
the plants were creeping over loose-growing Sphagnum or clambering 
over stocks of Carices, under circumstances where the lower leaf- 
surfaces were freely exposed to the air, the size of the leaf was 
increased to between 4 and 6 mm. 

The interesting point in these observations is that the plants in 
the first experiment assumed the habit of growth of Anagallis filifor- 
mis (Ch. and Schl.), where the stems attain a length of eight inches 
(20 cm.). This is a peculiar extra-tropical South American species 
growing in sandy and moist places in South Brazil (Primulacea? by 
Pax and Knuth, Pflanzenreich, 1905). Although at first regarded 
as a distinct species of the Tenella group of the genus, it is viewed 
in De Candolle's Prodromus as only a variety of Anagallis tenella ; 
and it is noteworthy that the species just named is not known either 
from South or from North America. The essential differences are 
slight, and are chiefly concerned with the degree of woolliness of the 
filaments and with the extent of the adhesion in their lower part. 
The stamens of the flowers were especially examined only in the 
second experiment, and displayed the characters of those of A. 



APPENDIX 



481 



tenella. In this species, as we learn from Pax and Knuth, the fila- 
ments are woolly along most of their length, and they unite to form 
a free tube one-third of their length. In A. filiformis the filaments 
are only woolly below their middle, and their cohesion concerns 
but a fourth or fifth of their length. 

Should any botanist in South Brazil be kind enough to send me 
specimens of Anagallis filiformis both in flower and in mature seed, 
I could try the effect of growing the plant under the conditions of 
an English peat-bog. 

Note 25 (p. 76). 

Sabine's record of the drifting of casks of palm oil from the 
Gulf of Guinea to Hammer f est. 

Sir Edward Sabine in one of the notes appended to his English 
edition of Humboldt's Kosmos (Vol. I., note 373, p. 454, 1846) gives 
particulars of a remarkable case of drift from the Gulf of Guinea to 
the vicinity of the North Cape, which naturally attracted the attention 
of Gumprecht, Fogh, Vibe, and others who have written on the 
subject. As evidence that portions of the cargoes of vessels wrecked 
on the coast of West Africa may reach Norway after making a double 
traverse of the Atlantic in the Main Equatorial Current to the West 
Indies and in the Gulf Stream to Europe, Sabine writes as follows : 
" Such an instance occurred when the Editor was at Hammerfest, 
near the North Cape of Europe, in 1823; casks of palm oil were 
thrown on shore belonging to a vessel which had been wrecked at 
Cape Lopez, on the African coast, near the Equator, under circum- 
stances which made her loss the subject of discussion when the 
Editor was in that quarter of the globe, the year preceding his 
visit to Hammerfest." The matter is also mentioned by Lady 
Sabine in her translation of Humboldt's Ansichten der Natur (Vol. I., 
p. 161, 1849). 

I have not found any fuller details of this wonderful drift, which 
is properly characterised by Gumprecht as the most interesting 
recorded fact, and by Fogh as sufficiently marvellous. These casks 
would have taken the course by the West Indies indicated by Sabine, 
and the only question arising in this respect is whether they reached the 
starting-place of the Gulf Stream in the Florida seas by way of the 
Caribbean Sea and the Gulf of Mexico, or in the Antillean Current 
skirting the northern and eastern shores of the Lesser Antilles. 
From the evidence given in Chapter III. the former course is most 
probable. The circumstance that not a single cask only but " casks " 
are stated to have been washed ashore at the same place, and appar- 
ently about the same time, after a drifting passage of from 10,000 
to 11,000 miles, discloses the first point for criticism. For reasons 
given in Chapter III. it is highly improbable that casks could keep 
together during a double traverse of the ocean, for which a period 
of at least two years would be needed. 

According to the tables given in Chapter III. the time occupied 
would be about twenty-six months by the Caribbean Sea route and 
about twenty-four months by the Antillean Stream route. Com- 
1 1 



482 



APPENDIX 



mander Campbell Hep worth's estimate for the first route, as quoted 
below, is at least thirty months. But Sabine's record would seem 
to suggest a period of only about a year, which involves an average 
drifting rate of from twenty-seven to thirty miles a day for the whole 
distance. Much depends, however, on the exact dates. If the 
interval between his visit to West Africa in 1822 and his sojourn 
at Hammerfest in 1823 covered the period between the early part 
of one year and the latter part of the other year, the objection against 
the excessive drifting rate would be to some degree removed. There 
remains, however, the question of the identity of the casks. 

In this difficulty I applied to Commander Campbell Hepworth, 
Marine Superintendent of the Meteorological Office, one of our 
leading authorities in matters connected with the Gulf Stream, and 
he very kindly gave me the following reply : " It is possible that 
casks of oil could be preserved long enough to drift to the north of 
Norway, but they would be so covered with barnacles, etc., that 
they would be unrecognisable. By a somewhat careful calculation 
I find that the drift would occupy at least 900 days, say, two and a 
half years." Then he proceeded to point out that the track would 
follow the course in the Equatorial Current via the Gulf of Mexico 
to the Strait of Florida, and subsequently northward and eastward 
to the Grand Banks, then through the Iceland-Faroe Channel to 
the north coast of Norway. I may add here that the possibility 
of this drift is increased by the behaviour of a bottle mentioned in 
the following note, which thrown into the sea close to the island of 
Ascension was recovered afloat off the coasts of Guernsey; but here 
a difficulty also arises, though it is concerned not with the identity 
of the drifting object, but with a possible confusion of dates, the 
genuineness of the actual drift being viewed as outside dispute. 

Note 26 (p. 76). 

A bottle- drift from Ascension to Guernsey. 

Major Rennell in his work on the Currents of the Atlantic, and 
Commander Becher in the Nautical Magazine for 1852 and 1854, 
refer to a bottle which on October 15, 1820, was thrown overboard 
about two and a half leagues north-east of Ascension from the Ameri- 
can vessel Lady Montague. It was picked up afloat off the western 
coasts of Guernsey on August 6, 1821, after an interval of 295. days. 
On these points both authors agree, and Rennell adds that notice 
was sent to the Admiralty. He rightly terms it "a remarkable 
instance," and assigns to it the route via the Caribbean Sea and by the 
Gulf Stream. But here we meet the same difficulty that was pre- 
sented by Sabine's casks of palm oil referred to in the previous 
note. To accomplish this passage of some 9000 miles between these 
dates a drifting rate of about thirty miles a day is needed. In this 
connection it is possible that there has been some confusion in the 
•dates. Rennell refers incidentally to a record of the Pique, as though 
there was another similar record; and whilst the starting-point 
given by him is in 7° 55' S. and 14° 23' W., the position assigned 



APPENDIX 



483 



in the Nautical Magazine for 1852 is 7° 7' S. and 8° 6' W., which is 
quite inconsistent with the statement associated that the bottle 
was cast over two and a half leagues north-east of Ascension. It 
is unfortunate that, as with Sabine's remarkable case of drift, there 
is here the suspicion of a doubt, which in neither case, however, 
affects the possibility of the passage, though in the one it is concerned 
with the identity of the casks and in the other with the dates assigned 
for the start and recovery of the bottle. 

Note 27 (p. 38). 
Bottle-drift on the Canary Islands. 

From what has been said in Chapters II. and III. it will be gathered 
that the Canary Group lies in the track of that portion of the seed- 
drift of the Gulf Stream which, after passing north of the Azores 
and approaching the European sea-border, is deflected south in the 
Portuguese or North African Current. Losing much of its materials 
on the shores of South-western Europe and on the coast of Morocco, 
the bulk of the residue traverses the Canaries, and continuing south 
turns westward near the latitude of the Cape Verde Group, finally 
reaching the West Indian region in the North Equatorial Current. 
All the records supplied by bottles and floats would therefore be 
expected to come from the north and north-west. The data to be 
now given indicate that this is actually the case, there being no 
records from the south. (The materials are supplied from the Ameri- 
can charts, the Prince of Monaco's papers, Dr. Schott's monograph, 
the Nautical Magazine, etc.) 

Of the twenty-eight bottle-drift records at my disposal, one came 
from the vicinity of Cape Sable (Nova Scotia), sixteen from the 
region between the Azores and the Banks of Newfoundland, one 
from off Cape Farewell (Greenland), and ten from the seas north of 
the Canaries, between the meridians of 13° and 18° W., and at dis- 
tances ranging from 500 to 1200 miles north of the group (37°-49° N). 
Though there is no record of a bottle or float from West Indian 
waters, several of the floats dropped over by the Prince of Monaco 
between the Azores and the Banks of Newfoundland must have 
begun their drifting passage in the middle of the track pursued by 
West Indian seeds across the North Atlantic ; and doubtless instances 
of stranding on the Canaries would have been forthcoming with 
more extensive data at one's disposal. 

The daily rate of the drift from the North-west Atlantic to these 
islands is evidently small. Of 996 floats thrown over in 1887 by 
the Prince of Monaco between the Azores and the Great Bank of 
Newfoundland (including sixty-five from positions to the north of 
the Azores), 142 were recovered, and of these fourteen (10 per cent.) 
were found on the Canary Islands. The mean daily drift of the 
five recovered in the shortest time is placed by him at 5*32 miles. 
If we place the average distance traversed at about 2000 miles, 
about a year (376 days) would be covered in the passage. A period 
of only six months between the times of the start and recovery is 



484 



APPENDIX 



implied in the Nautical Magazine for 1852 in the case of a bottle 
(No. 102) thrown over in November 1835 about forty miles south 
of Cape Sable (Nova Scotia), and picked up in May 1836 on the island 
of Fuerte ventura (Canaries). The distance traversed would not be 
less than 3600 miles, which gives a daily rate of about twenty miles, 
an estimate that is very excessive for the traverse of this part of 
the North Atlantic, and it is likely that there has been a printer's 
error here, as affecting the dates. 

One of the most interesting of the records for the Canary Islands 
is given by Rennell in his work on the Currents of the Atlantic. 
When in command of H.M.S. Hekla in lat. 58° 13' N. and long. 
46° 55' W., about 140 miles S.W. of Cape Farewell (Greenland), 
Captain Parry threw over a bottle, which rather over two years 
afterwards (June 16, 1819, to July 29, 1821) was recovered on 
Teneriffe. This is evidently the " enigmatical drift " (rathselhafte 
Trift) to which Dr. Schott, quoting the Physical Atlas of Berghaus 
(1837), alludes in his paper (p. 1). It does not, however, appear 
to be quite so mysterious when we reflect that four bottles thrown 
over by Captains Parry and Ross in Davis Strait, 1818 to 1821, 
between 59° and 65° 40' N. lat., were found between eight and fourteen 
months afterwards floating off and stranded upon the coasts of North- 
west Ireland, West Scotland, and the Outer Hebrides. All of them 
must have got into the main track of the Gulf Stream, and we have 
seen in the earlier chapters of this work that Gulf Stream drift may 
be stranded anywhere on the coasts of Europe between the North 
Cape of Norway and Morocco, and that no inconsiderable portion 
of it may be returned by the way of Madeira and the Canaries to 
the West Indies. If, therefore, drift can reach the Irish and Scottish 
coasts from Davis Strait, the passage of drift from Cape Farewell to 
Teneriffe would be quite probable (see Note 35). 

Note 28 (p. 38). 

The bottle-drift of Madeira. 

All that has been said in the previous note of the Canary Islands 
might be expected to apply to the neighbouring islands of Madeira, 
which lies in the course of the same North African or Portuguese 
Current— a current representing the southerly deflection of the great 
North Atlantic easterly surface- currents that bear the Gulf Stream 
seed-drift to Europe. Like the larger islands of the Canaries, Madeira 
is ill-adapted for receiving and holding bottle-drift, and the records 
are scanty. But they are sufficient to show that we have here the 
same story of drift from the North-west Atlantic and from the seas 
in European latitudes to the north of the island, none coming from 
the south. 

The Prince of Monaco gives six records for floats that were recovered 
in Madeira after being dropped overboard in 1885 and 1887 in the 
region between the Azores and the Banks of Newfoundland. In 
the American charts there is the record of a bottle (October 1908, 
No. 4) which reached Madeira from a position about 400 miles due 



APPENDIX 



485 



north of the large islands of the Western Azores. With reference 
to bottles arriving from European latitudes to the north of Madeira, 
Schott gives a record (No. 24, map 2) and the American charts 
give another (March 1909, No. 98). Here the bottles reached the 
island after being cast over 300 to 360 miles N.N.E. The average 
daily rate for this part of the Atlantic would be about five miles. 
It is highly probable that West Indian drift after traversing the 
Atlantic in the Gulf Stream track is at times diverted to Madeira ; 
but the records of bottle-drift at my disposal are too scanty to afford 
a direct indication of this fact. 



Note 29 (p. 38). 
Sargasso or Gulf weed in Azorean beach-drift. 

The Sargasso weed is only represented by scattered fragments 
more or less incrusted with polyzoa. Gulf weed seems to be rarely 
carried eastward of the group except in this condition. Captain 
Ostboe of the fruit-steamer Fix, who had accomplished about eighty 
voyages between London and Hamburg and the Azores, told the 
writer that he had never seen living patches of Sargasso, such as 
are met with a few hundred miles to the south-west of the islands. 
Authorities vary somewhat in placing the north-east limit of the 
Sargasso Sea. All, however, place it to the southward and west- 
ward of the group, and if we regard the nearest approach as 250 
or 300 miles south-west of Flores we shall probably be near the 
limit. It is possible that during south-west gales the living weed 
may reach the islands, but I found no fragment that did not indicate 
a prolonged flotation of months in the dead state. The south-east 
trend of the currents would under ordinary circumstances only 
permit its approach from the north-west far beyond the area where 
the living weed is found. 

It would, indeed, appear probable that the fragments of dead 
Sargasso which reach the Azores have accompanied the drifting 
West Indian seeds in their circuitous passage from the Florida seas 
past Cape Hatteras, as described in Chapter III. Sargasso weed 
seems to possess a fugitive vitality outside its usual waters. 
Rennell in his work on the Currents of the Atlantic Ocean (p. 183) 
refers to the observations of Lieutenant Evans, who contrasts the 
great masses of living weed that were met with in the Gulf of Mexico 
with the old brown patches of the weed covered with " barnacles " 
observed in the Florida Stream. 

Walker in his book on the Azores (p. 47) speaks of quantities of 
Sargasso weed being washed ashore at certain seasons of the year 
on Graciosa, the islanders employing it for fertilising the land. It 
is likely that this is not the true Sargasso, but another weed altogether. 
The people of Magdalena at the west end of Pico, give the name, 
as the present writer ascertained, to quite another sea-weed that 
was washed up in abundance during the heavy north-west gales 
that prevailed during his sojourn there in March. Like the Graciosa 
men they use it for enriching the soil. They are familiar with the 



486 



APPENDIX 



true Sargasso, but they call it " Plante do Golfe " (Gulf weed). The 
other weed evidently grows around the coasts, and is torn off by the 
breakers in heavy weather. In this connection it may be noted that 
fragments of true Sargasso have been found on the coasts of Cornwall 
and on the Shetland beaches, probably in the dead state. 

Note 30 (p. 210). 
Iguanas, snakes, and alligators, in the Turks Islands. 

It is probable, that iguanas, snakes, and alligators were all of them 
frequent in these islands before their occupation by white men. 
The iguanas have been exterminated on all but two or three of the 
islands. The snakes are now confined to a single cay. The alligators 
have disappeared, and as their presence would not have been welcome 
on such small islands they were doubtless effectually destroyed. 
There can be no difficulty in explaining the existence of snakes and 
alligators on these islands, since San Domingo lies only about a 
hundred miles distant from the southernmost cay. 

Large snakes and crocodiles are known to have been transported 
alive across far broader tracts of sea. For instance, they have 
reached Keeling Atoll that lies 700 miles from land in the Indian 
Ocean. When on the atoll in 1888 I was told of three or four living 
snakes and of a living crocodile that had been stranded there on 
drift-wood some years before. (See my paper on Keeling Atoll in the 
Journal of the Victoria Institute of London, 1889.) That this attempt 
on the part of nature to re-stock the atoll with snakes and crocodiles 
is always going on is evidenced by the remarks of Wood- Jones, who 
was on the Keeling Islands in 1905. He refers to the preservation 
in the Governor's house of the skulls of two crocodiles that had been 
shot on the atoll after arriving in this fashion. Many snakes must 
have reached the islands since my visit, clinging as he says, to floating 
drift. " There are several instances " (he writes) " of large snakes 
having been killed in the atoll, and others have been picked upon 
the beach " (Coral and Atolls, 1910, p. 295). 

There must be several records of this kind relating to the West Indian 
region. Purdy in The Columbian Navigator (1839, III., 31) makes 
the following interesting note : " Some years back a very large cedar 
came on shore at Sable or Sandy Bay (St. Vincent), bringing with it 
a large female boa constrictor, which took to the neighbouring wood, 
and when shot, some days after, was found to contain many young 
ones, nearly ready to escape; and which, but for the destruction 
of the old one, would have taken up their abode in the woods." 
I may add that large snakes of this description exist on the island 
of Tobago about 100 miles away; but it would seem most likely 
that it arrived at St. Vincent with Orinoco drift, and in that case 
the distance traversed in the swift equatorial current would have 
been about 300 miles. 

The following notes are taken from my journal in the Turks Islands. 
Although the large iguanas evidently once existed on all the islands 
of this small group, they seem now (1911) to be principally, if not 



APPENDIX 



487 



entirely, restricted to the uninhabited islands of Long Cay and Greater 
Sand Cay. In the last named they are particularly abundant, in 
spite of the fact that numbers are captured by fishing parties of the 
coloured natives from Salt Cay and Grand Turk that from time to 
time make a brief sojourn there. The fruits of Genipa clusiifolia 
(Seven-year Apple) are evidently appreciated by these reptiles; 
and it is remarked, when dealing with this plant, that the two islands 
now frequented by them are just those where the Seven-year Apple 
grows in greatest quantity. Reference has already been made 
(p. 277) to the allusion to the iguanas of the Turks Islands in the 
Annual Register of 1764 (Watkins). As a change from salt-pork, 
we are told that the flesh of these creatures was much prized by the 
early Bermudian salt-rakers. Iguanas formed a staple article of 
diet of Bahamians in Catesby's time, about 1725 (II., 64) ; and they 
are still appreciated by the coloured people of the Turks Islands. 
We brought back with us to Grand Turk from Greater Sand Cay 
a number of iguanas alive in a sack; and I learned that they are 
often transported to Grand Turk and Salt Cay from the islands in 
which they abound. Not improbably the Caribs did the same 
when carrying provisions for their voyages ; and it is not unlikely 
that they intentionally stocked with these reptiles some of the 
isolated cays of the Bahamian seas which served as resting-places 
during their passages. 

The existence of a large snake on Eastern Cay was reported to 
me by several persons familiar with that island; but it did not 
come under my notice during my two visits in February 1911. 
Alligators are not now known to exist in the group ; but about two 
years before my stay there a dead alligator was found on a beach 
in Cotton Cay partially buried in the sand. The postmaster, Mr. 
Lea Smith, whose brother had made the discovery, informed me that 
it was probably washed ashore in a dead or dying condition. These 
reptiles would even now find congenial surroundings in the mangrove 
swamps of South Creek in Grand Turk ; and it is more than probable 
that they originally infested these islands, having been exterminated 
by the inhabitants. 

Note 31 (p. 408). 
Draccena draco (Dragon-tree). 

This interesting tree, w T hich is confined to the Canaries, the Madeiras, 
and the Cape Verde Islands, though in the last two nearly or quite 
extinct, specially attracted my attention on Teneriffe, as I had been 
previously familiar with Dracaena aurea, the peculiar Hawaiian 
species, which is the only representative of the genus in Polynesia. 
Of the forty species distributed over the warmer parts of the Old 
World, these two on account of their restricted range are amongst 
the first to draw the attention of the student of distribution. 

Whilst still well represented in the Canaries, favouring, as Dr. 
Christ remarks, the steep sides of the rocky ravines and gorges as 
they descend to the coast, it seems to be almost extinct in Madeira. 
In fact, it is stated that Webb a couple of generations ago saw the 



488 



APPENDIX 



last Madeiran plant. Yet Lowe in his Manual of the Madeiran 
flora (1857) includes it amongst the very rare indigenous plants. 
In the Cape Verde Islands it was recorded only from St. Antonio, 
but as a cultivated plant, by Schmidt in the middle of last century 
(Flora der Cap Verdischen Inseln, 1852). However, Hemsley in 
Science Progress for 1894 (Vol. II.) states that it is still said to exist 
here and there in the mountains of St. Antonio and St. Nicolas. 
But it is not named by Prof. Coutinho in the list of the plants 
of the islands in his Catalogas Herbarii Gorgonei Universitatis 
Olisiponensis, Lisbon, 1914-15. It may be added that although 
the tree is not a native of the Azores, it is to be occasionally observed 
in gardens as on Pico and on San Miguel. 

In addition to the numerous solitary specimens of the Dragon- 
tree planted in and near towns on Teneriffe, I came upon it in 1906 
growing wild on the Taganana coast near the north-east extremity 
of the island. Here in the company of the cactoid Euphorbia (E. 
canariensis) it grows on the faces of rocky declivities in inaccessible 
parts of the precipitous slopes of the Roque de las Animas, a pinnacle 
mountain rising 1400 or 1500 feet above the sea. Though growing 
singly, there were several trees scattered about on the mountain-side 
in situations suggestive of dispersal of the seeds by birds. Its station 
may be compared with that of the Hawaiian Dracaena aurea, which 
is not uncommon in the open wooded districts up to 3000 feet, but 
grows in a variety of situations. Thus, I found it once in the broken- 
down caverns of an old lava-flow frequented by pigeons that doubtless 
brought the seeds. 

Hillebrand gives no affinities for the Hawaiian species; but Sir 
Joseph Hooker has some very suggestive reflections on Dracaena 
draco in one of the appendices of his book on Marocco and the Great 
Atlas, where the Canarian flora is discussed (pp. 410, 417). It has, 
he says, " only one near ally, D. ombet, which is confined to Abyssinia, 
Southern Arabia, and the intervening island of Socotra." He suggests 
the hypothesis that at a very remote period this Draccena, together 
with the tropical trees of Myrsinece, Laurineae, etc., that belong to 
the Canarian flora, flourished in the area included in North-west 
Africa and its adjacent islands, and that they have been expelled 
from the continent by altered conditions of climate. In this connec- 
tion he also links with the Draccena the Sapotaceoe of Madeira and 
the Cape Verde Islands, plants that in the islands of the Pacific and 
elsewhere raise much the same issues. This explanation seems very 
probable as concerning Draccena draco, but it could not be applied 
to the Hawaiian plant. 

Let us look for a moment at the modes of dispersal possessed by 
Dracaenas generally. Though in the cases of the Canarian and 
Hawaiian species the seeds even after prolonged drying possess no 
buoj^ancy, being in this respect doubtless typical of the genus, 
the berries would readily attract birds. The seeds of Dracaenas 
are indeed well fitted for withstanding a transport in a bird's stomach, 
the small embryo being protected by a very tough albumen. But 
whether they could be thus carried unharmed across the 3000 to 
4000 miles of ocean that intervene between the eastern borders of Asia 



APPENDIX 



489 



and the Hawaiian Islands is another matter. Yet in Hawaii, Draccena 
aurea shares this difficulty with several other trees, such as Sider- 
oxylon (Sapotacece) and Elceocarpus, that are known in other localities 
to be locally dispersed by pigeons (Plant Dispersal, pp. 372-4, 377). 

One point that should be remembered in connection with the survival 
of species of Dracaena on islands is the tenacity of life displayed by 
D. draco in the Canaries. That the tree would make a vigorous 
effort to contest extinction is indicated not only by the manner of 
its growth, but also by its capacity of vegetative reproduction. 
Not only can it be raised from cuttings ; but it seems highly probable 
that if the tree was greatly injured by the wind, so that it lay in 
fragments on the ground, it would sometimes be able to reproduce 
itself from the tops of the branches. An experiment by Mr. Bain 
in this direction is recorded in the ninth edition of the Encyclopaedia 
Britannica (XII., 236). After the top of a Dracaena draco, which 
had been slowly separated from the stem, had been suspended some 
months in a bushy covering, it protruded roots, and subsequently 
established itself when lowered into the soil. 



Note 32 (p. 265). 
A comparison of the old and later charts of the Turks Islands. 

Here are compared a French chart of 1753 and the British Admiralty 
chart mainly based on the survey of 1830. The French chart, which 
is in the British Museum library, describes itself as " from a survey 
made in 1753 by the sloops VAigle and VEmeraude by order of the 
French Governor of Hispaniola with improvements from observations 
made in 1770 in the Sir Edward Hawke, King's Schooner." It was 
published in 1794 by Laurie and Whittle, 53 Fleet Street, London ; and 
is drawn on a scale of three inches to four miles. The Admiralty 
chart (No. 1441) is based on Captain Owen's survey of 1830 with 
additions to 1845 and large corrections in 1864-5 and 1898, the scale 
being much the same as in the French chart. 

The names of the larger islands in the French chart are those in 
present use. Thus we have Grand Turk, Cotton Island, Salt Key, 
and Sand Key ; but the last, which is now known by the inhabitants 
as Greater Sand Key, is there stated to be " sometimes called Foul 
Key or Seal Key." The names of the smaller islands are all different 
from those in the Admiralty chart which are those now employed in 
the group. Thus Long Key is there named Pelican's Island, Pear 
Key is Bird's Island, Eastern Key is Breeches Island, and Toney 
Rock to the south of Eastern Key is called The Centry. Gibb Key 
and Round Key are named The Twins. However, the small eastern 
islands are only rudely indicated in the French chart, and Penniston 
Key is omitted altogether — an evident error, since it could not be of 
recent origin. 

For nautical surveys in those times and in those seas, this early 
French chart may be regarded as fairly complete. Three fixed posi- 
tions were obtained by astronomical observation, the latitude and 
longitude for the south-west corner of Grand Turk, and the latitude 



490 



APPENDIX 



for the middle of Salt Cay and the middle of Greater Sand Cay. 
The error in the longitude, as compared with the Admiralty chart, 
is about forty minutes on the minus side, and that of the latitude 
ranges from almost nothing to two miles. Except in the case of 
Grand Turk, the dimensions of the larger islands as given in both 
charts do not differ greatly — the length of Grand Turk in the French 
chart being three and three-quarter miles instead of nearly five and 
a half miles as in the later chart. Unfortunately the period for the 
valid comparison of the two charts is limited to only sixty years, 
namely, between 1770 and 1830, since the additions are not dis- 
criminated in either case. 

The soundings in the French chart, though far fewer than in the 
Admiralty chart, are fairly well distributed over the bank. The 
comparison, as far as it goes, indicates that the maximum depths 
over the bank were the same at the time of the French survey as 
they were during the English survey. But the depths were more 
uniform; and evidently the numerous shoals that now exist in 
different localities between the islands, as between Grand Turk and 
Cotton Cay, were not charted by the early surveyors. The limits of 
the bank are imperfectly determined in the French chart; but one 
or two areas lend themselves for comparison. All the area of the 
bank lying south and east of a line drawn from Greater Sand Cay 
through Salt and Cotton Cays to Pear Cay, and thence north-east to 
the edge of the bank, displays a uniform depth in the French chart 
of nine or ten fathoms. This is in a general sense the depth-condition 
exhibited in the Admiralty chart over the greater part of this area, 
except amongst the cays between Salt Cay and Toney Rock. Here 
soundings of seven and eight fathoms prevail towards the edge of 
the bank, and further in amongst the cays numerous shoal patches 
covered by less than three fathoms of water exist, the prevailing 
intervening depths being about five fathoms. 

Considerable changes seem also to have occurred in the area 
between Cotton Cay and Grand Turk. Here the sea is so beset with 
shoals and reefs that, as I know from my own experience, navigation 
at night is dangerous. In the French chart it is credited with a 
uniform depth of three and four fathoms, three in the northern half 
and four in the southern half of the area. In the Admiralty chart, 
although maximum depths of three fathoms in the northern third 
and of four and five fathoms in the southern two-thirds are indicated, 
numerous shoals, often with rocks awash, are also marked. Reef- 
growth has evidently been active in these waters since the time of 
the French survey, and it is probable that Lesser Sand Cay, a con- 
spicuous sandbank midway between Grand Turk and Cotton Cay, 
on which vegetation at times gains a hold, did not then exist. 

With reference to the changes in the islands indicated by a com- 
parison of the two charts, the most noticeable one is the filling up 
of a channel two feet deep, which in 1753-70 cut off the northern 
third of Greater Sand Cay. In Captain Owen's chart the island 
appears to consist of two parts connected by sandbanks that are 
covered at high-water. But it may be that this was its condition 
in 1898, when the last important additions were made. At the 



APPENDIX 



491 



present time, as I was informed, the neck of sand south of Beacon 
Hill is sometimes breached by the seas during stormy weather. In 
1911 the islet off the north-east side was separated by a narrow, 
shallow passage nearly exposed at low-water. 

A puzzling feature in connection with Grand Turk is that the 
North Creek is represented in the Admiralty chart as cut off from 
the sea to the north by a tract of low land half a mile broad. This 
seems inexplicable. The present condition is well brought out in a 
map of the island made in 1902-4 by J. F. Osborn, Colonial Sur- 
veyor, where it is shown that the North Creek approaches within 
about 300 yards of the sea, with which it once communicated by a 
broad passage, 200 yards across, that is now more or less silted up. 

In connection with Greater Sand Cay there is a note in the old 
French chart to the following effect : " Upon this Bluff (the southern 
end of the island) the French, after the late Peace, erected a Sea 
Mark, which they were soon after obliged to demolish." This may 
perhaps explain a reference to this island in the West India Pilot, 
Part III., p. 370, 1909, where it is stated that 44 the remains of some 
remarkably solid masonry on the cay are similar to those which may 
be seen at Cape Isabella on Santo Domingo-Haiti." 

Note 33 (p. 361). 

Plants collected by George Forster in Fayal (Azores) in 1775. 

(Commentationes Societatis Regice Scientiarum Gottingensis, Vol. IX., 
1787. The paper is entitled " Plantse Atlanticse ex insulis Madeirae, 
St. Jacobi, Adscensionis, St. Helense, et Fayal reportatse." The 
species are stated to be all Linnean. A indicates that the species 
has not since been recorded from Fayal but from other islands of the 
group. F indicates that it has since been found by Watson, Brown, 
and others on Fayal.) 

F. Verbena officinalis. 
F. Cyperus esculentus. 

Cyperus compressus. 
F. Milium lendigerum (= Gastridium lendigerum, B.). 
F. Polycarpon tetraphyllum. 
F. Scherserdia arvensis ( = Sherardia arvensis). 

Borago officinalis. 
F. Physalis peruviana. 
F. Solanum pseudo-capsicum. 

Nerium oleander. 

Gentiana centaurium ( = Erythraea ramosissima, Pers. I K). 1 
A. Erica scoparia. 2 
F. Reseda luteola. 

1 It seems likely that Eryihraza centaurium, Pers., is here meant. It is now common 
over the group, including Fayal, and was found by Hochstetter as far back as 1838. 

* Trelease suggests that the true Erica scoparia, L., which was found on the island 
off Villa Franca (San Miguel) by Hochstetter, was merely a form of Erica azorica, 
the common Tree-Heath of the islands. This, however, appears unlikely, since 
Hochstetter himself differentiated the Azorean species. 



492 



APPENDIX 



F. Mentha rotundifolia. 
F. Mentha pulegium. 

Malva mauritiana ? 1 
F. Spartium junceum. 
F, Vieia sativa. 
A. Ornithopus perpusillus. 
F. Trifolium arvense. 
F. Lotus angustissimus. 
A. Hypericum perforatum. 
F. Hypericum humifusum. 
F. Crepis virens. 

Hypocharis radiata (= Hypochoeris radicata). 2 

Carthamus tinctorius (Safflower). 
F. Gnaphalium luteo-album. 
F. Pteris aquilina. 
F. Asplenium marinum. 

Lycopodium plumosum. 

These plants were collected during a stay of four or five days in 
July 1775, made by the Resolution under Captain Cook. Of the 
thirty species above named, three-fourths are included in Watson's 
catalogue. This proportion would be considerably increased if we 
dealt with the species of Gentiana, Malva, and Hypochoeris, as indi- 
cated in the footnotes, and considered that the Safflower and the 
Oleander as cultivated plants would have been excluded by Watson 
altogether. 

With the exception of the two ferns and the lycopod there is 
hardly a plant in this list that could be regarded as having been 
present in the Azores before the discovery of the group in the first 
half of the fifteenth century. Of the flowering plants two-thirds 
are weeds of cultivated and waste places, many of which are known 
to have been spread through man's agency over much of the world. 
Others, such as the species of Physalis, Solatium, and Spartium, as 
well as Cyperus esculentus, are stated by Watson and Trelease to 
have been introduced, or are labelled as weeds without comment, 
and most of them are well known to be plants, as in the first three 
cases, that have often been introduced by man, either intentionally 
or accidentally, in other parts of the world. The Safflower and the 
Oleander, as above indicated, are not included by Watson and 
Trelease in their lists of plants, either indigenous or introduced. 
They may be observed in the small cottage gardens and ornamental 
gardens of our own time. 

The above list is useful as showing that many of the plants that 
do not belong to the Azorean flora were introduced long ago. Most 
of them, it is true, were observed by Hochstetter in 1838, but for 
the plants it concerns this list carries us sixty-three years further 
back. Within a year or two of each other, George Forster (1775) was 

1 Malva nicceensis, AH., collected by Watson and Godman only in Fayal, was in 
the first place named by the former M . rotundifolia. 

2 Possibly Hypochoeris glabra, L., which much resembles H. radicata, L. (B. and 
H.), and has been since found on Fayal and other islands. 



APPENDIX 



493 



collecting the weeds and Francis Masson (1777-8) was enriching the 
gardens at Kew with the indigenous trees and shrubs of these islands 
(Aiton's Hortus Kewensis, 1789). Yet if man's interest is more 
attracted by the second, the history of our race is intimately bound 
up with the first, and weeds offer from this standpoint almost virgin 
ground for the investigator. 

Note 34. 

Observations on the medanos or moving sand-hills of the Ancon 
coast region in Peru. (General remarks on this subject will be 
found on p. 271). 

The following observations were made in February 1894 in the 
Ancon district north of Callao. Broad, sandy, and almost barren 
plains extend inland from the shores of Ancon Bay for about three 
miles to the foot of the mountains, rising in that distance 200 to 300 
feet, the sand on the plains being only a foot or two in depth. A 
sand-covered spur of the mountains descends to the coast on the 
south side of the Ancon plains, having an elevation opposite the 
town of 400 feet. Immediately south of the spur is a large sandy 
beach, the Playa Mayor, more than a mile in length, which was the 
starting-place of a line of medanos that at the time of my visit took 
an oblique north-easterly course before the prevailing south-west 
winds of four and a half to five miles to the base of the inland range 
of mountains. The whole of the region here concerned up to an 
elevation of 500 feet was only a sandy waste, where a tumble-weed 
of the genus Tillandsia alone found a home. 

As typically displayed, these sand-hills are crescentic in form, 
twenty-five to thirty feet across, and six to ten feet high, the con- 
cavity being in front. That they are ever advancing was indicated 
by the way in which they lay astride the beaten tracks. I observed 
these medanos after they had reached in irregular order the top of 
the spur overlooking the Ancon plains. One was perched on the 
crest at an elevation of 200 feet above the beach, another on the 
crest at 300 feet, and a third at 360 feet. Before a light wind with 
a force of about three the sand was steadily moving across the crest, 
the heavier particles along the surface and the lighter blown through 
the air. In ten minutes, sand of the weight of 108 grains was blown 
into the mouth of a round tube, an inch in diameter, that had been 
placed on the surface. I felt a light rain of sand on my face as I 
sat watching, and when the wind freshened for a few moments my 
face was " peppered " with sand. All the sand of the surface was 
in motion on the crest, both on the medanos and in the spaces 
between them. I noticed that after the medanos had crossed the 
ridge they re-formed in an irregular fashion on the descending 
slopes, unless the descent was steep, when the sand formed a con- 
tinuous slide. On reaching the plains, 200 to 350 feet below, the 
medanos resumed their typical shape and gathered into line, or 
rather into column, for the traverse of the plains. Arranged two 
or three irregularly abreast in a column about 100 paces in width, 



494 



APPENDIX 



the medanos crossed the plains obliquely in the same north- easterly 
direction for about three miles to the foot of the mountains, ascend- 
ing the lower slopes about 500 feet, and here the sandy area termi- 
nated. In their traverse of the plains this column of medanos 
crossed two hill ranges that rose 100 and 150 feet above the plains. 

By careful measurements on three medanos I ascertained that in 
five days they had advanced about a foot, the prevailing winds 
being light and from the south-west. From time to time slides take 
place down the steep face of the concavity, the sand caking a little 
on the surface and forming layers, a half to an inch thick, that 
slide to the bottom. Impelled by fresh winds, the medanos may 
move yards daily, and when driven by violent winds, as we learn 
from Dr. von Tschudi, the medanos pass rapidly over the plains. 
Strewn over the ground all over the medano region is a much coarser 
sand that could be moved only by strong winds. It is arranged in 
wavelets about two feet apart and one to three inches high, and 
remains at rest when the lighter medano sand is moving briskly 
along. 



Measurements of the Sand -grains in the Region of Medanos (moving 
Sand-dunes) in the Ancon Coast-district of Peru. 





Finest 
Material aver- 
aging "2 mm. 

in size 


Medium 
Material aver- 
aging - 3 mm. 


Coarse 
Material aver- 
aging 5 mm. 


Extra-coarse 
Material aver- 
aging 1-2 mm. 


Sand blown through the 
air a foot above the ground. 


95% 


5% 






Sand blown along the 
surface of the ground. 


80% 


20% 






Sand of a typical meda- 
no four miles from the 
starting-place above the 
beach. 


55% 


44-5% 


0-5% 




Sand of a typical meda- 
no one mile from the 
starting-place above the 
beach. 


41% 


58% 


i-o% 




Drift sand blown up the 
hill-slopes 30 feet above 
the beach just mentioned. 


11% 


69% 


20% 




Sand from the wavelets 
spread over the medano 
plains. 








100 % 



Note. — The prevailing winds were light with an average force of three. 



The sand is derived from the disintegration of andesitic rocks. It 
is composed in their order of frequency of grains of felspar, magnetite, 
semi-vitreous volcanic rocks, pyroxene, quartz, brown mica, horn- 



APPENDIX 



495 



blende, etc., calcareous particles being either absent or very scanty. 
The magnetite mostly gathers among the finest materials, being 
there especially frequent in the sand blown along the ground and in 
the medanos that have travelled four miles from their starting-place, 
the proportion making up 25 or 30 per cent, of the total. It is also 
well represented amongst the finest materials of the sand blown 
through the air. The grains of magnetite are always smaller than 
those of the felspar. Thus in the case of the sand blown through 
the air the magnetite grains average 0*12 mm. in size and the felspar 
grains as much as 0'23 mm. The beach sand from between the tide- 
marks has the same composition as the sand of the medanos and of 
the plains. 

It is interesting to notice how the fine materials are appropriated 
by the medano as it proceeds inland from the coast. In the beach 
sand blown up the hill-slopes, but below the place where the first 
medano shapes itself, there is only 11 per cent, of fine materials. 
When the medanos have travelled a mile inland the proportion is 
about 40 per cent., and when they have extended four miles from 
the starting-place it is 55 per cent. Except when composed of 
softer calcareous materials, as in the case of the seolian deposits of 
the Bahamas, " the ordinary drifted sands of seaside dunes show 
little rounding " (see Grenville Cole's Practical Geology, 1898, p. 189). 
This is especially true of the dunes or medanos of the Ancon district. 
The sand-grains of the medanos four miles from the beach were 
most affected by attrition; but even they could only be described 
as sub-rounded. The sand-grains of the medanos a mile from the 
starting-place and the sand blown through the air were still less 
rounded, and could be only termed sub-angular. The extra-coarse 
sand of the wavelets or ripplets spread over the surface of the medano 
plains, however, displayed the effects of attrition in a marked degree, 
the angles of the grains being well rounded. 

Note 35 (pp. 55, 484). 

Bottle-drift in high latitudes of the North Atlantic. 

The tracks are given in the American charts for several bottles 
thrown into the sea between Newfoundland and Greenland which 
were cast up on the coasts of Ireland, Scotland, and Norway, reach- 
ing even to the North Cape, the velocity of the swiftest being eight 
to nine miles a day. One, however, dropped over about 100 miles 
south-east of Cape Race, was recovered on the south coast of Iceland 
sixty-seven days afterwards, the distance of 1950 miles having been 
accomplished at a minimum daily rate of twenty-nine miles (see 
No. 95 in the U.S. Pilot Chart of the North Atlantic for November 
1908). The most northerly traverse of the North Atlantic that is 
illustrated in the American bottle-drift charts is one marked 109 in 
the U.S. chart just named. Here a bottle drifted from a position 
about 300 miles south-east of Cape Farewell to the North Cape of 
Norway. However, through a printer's error, the daily rate is given 
as 34*6 miles instead of 3*46 miles. But bottle-drift from off the 



496 



APPENDIX 



southern end of Greenland is just as likely to be carried south in its 
traverse of the Atlantic. Rennell mentions a bottle that was re- 
covered on Teneriffe rather over two years after it had been cast 
over from H.M.S. Hekla (Captain Parry) on June 16, 1819, in a 
position about 140 miles south-west of Cape Farewell. This is 
evidently the " highly remarkable and even enigmatical drift " to 
which Dr. Schott refers on the first page of his memoir, though he 
here quotes from the Physical Atlas of Berghaus. However, in the 
light of facts to be now given the track of this bottle loses a little of 
its remarkable character. 

Rennell gives the records of four bottles thrown over in Davis 
Strait in 1818 and 1821 by Captains Parry and Ross, the northern- 
most in lat. 65° 40'. After periods of from eight to fourteen months 
they were recovered on the coast of Donegal (two cases), the west 
coast of Scotland, and the Hebrides. Two of them dropped over 
within two days of each other and about three degrees of latitude 
apart (62° 5' and 59° 8') were found afloat within a fortnight of each 
other, thirteen and a half and fourteen months afterwards, off the 
Donegal coast and off the Isle of Staff a (W. Scotland). 

Note 36 (p. 388). 

The wells of Pico in the Azores. 

Just as on San Miguel and other large islands of the group, there 
are no permanent rivers and but few surface streams on Pico ; but as 
the frequent occurrence of the local name of "Ribiera" indicates, 
there are numbers of torrent-beds and watercourses, which, although 
they carry off the water after heavy rains, are dry during most of 
the year. One of the sights of the great cone of Pico is the deep 
gorge of the Ribiera Grande, which has been scooped out of the 
precipitous mountain-side to the east of San Mattheus, the slopes 
rising up from the coast to a height of 3000 feet within half a mile. 
It is probable that at the time of their discovery, when the islands 
of the Azores were densely wooded, the streams were more permanent 
in their character. Generally speaking, on the island of Pico at the 
present day the only surface water is the standing water of the 
upland swamps and of the mountain lakes and ponds. I did not 
come upon any thermal springs on this island, nor does there appear 
to be any stream of a permanent character partially fed by hot 
springs, such as we find in the case of a stream draining the Furnas 
Valley in San Miguel, which empties into the sea at the village of 
Ribiera Quente. 

The condition of things on the island of Pico is probably to some 
degree typical of the other large islands of the group, excepting 
perhaps San Jorge. There are no springs on the great mountain, 
and apparently but few in the eastern part of the island. Yet fresh 
water oozes into the sea all around the coasts. Those of the peasants 
of the coast villages, who are too poor to build a covered rain-tank 
of masonry, obtain their water supply from wells sunk in the rubble 
of large and small blocks of lava immediately behind the beach. 



APPENDIX 



497 



Probably most of the water issues at the coast between the tide- 
marks, and it is here that women living far from a well often wash 
their linen. 

The seaward soakage of the underground waters is a frequent 
phenomenon around the shores of lofty volcanic islands, or of high 
volcanoes rising like that of Etna near the sea. Often the water 
gathers in subterranean streams which emerge at the coast and in 
the depths beyond, as I have described in the case of Hawaii and 
Etna in the first volume of my Observations of a Naturalist in the 
Pacific (p. 38). In Pico, as above observed, it displays itself chiefly 
in the oozing of fresh- water between the tide-levels on the beaches. 

At times the seaward soakage of underground waters gives rise to 
a number of subterranean streams of fresh-water that well up in the 
sea off the coasts of large islands. Mr. Samler Brown in his Guide 
to Madeira and the Canary Islands (1905, e, 22; i, 2) refers to the 
streams of fresh-water that rise up in the sea near the coasts of those 
islands. In La Palma, for instance, much of the rainfall on the 
wooded slopes of the mountains " niters through into the sea at 
short distances from the coast-line." My readers will recall Hum- 
boldt's reference to the occurrence, a few miles off the Gulf of Xagua 
on the south coast of Cuba, of very extensive fresh-water springs, 
from which ships can water (Lady Sabine's translation of Ansichten 
der Natur, I., 161). But submarine springs may exist along con- 
tinental coasts, even where there is no great elevation. Thus Dr. 
Scharff in his book on The Origin of Life in America (1911, p. 169) 
quotes Prof. Shaler to the effect that along the coasts of Florida 
there arise from beneath the sea a number of submarine springs. 

But to return to the subject of the coast wells of Pico, it may be 
observed that the water is always a little brackish. As with those 
of San Mattheus, Magdalena, Caes-o-Pico, Praynha do Norte, and other 
places at the sea-border, the wells have sometimes to be sunk to a 
depth of fifteen to twenty feet, the level of the water being that of 
the sea. But their water is in summer much cooler than that of the 
sea. At 5 p.m. on July 28, when the temperature of the well-water 
at Praynha do Norte was 60° Fahr., that of the sea was 72-5°. Per- 
manent springs, as I have said, are only to be found off the great 
mountain, and they are few in number. However, the coast village 
of Santo Amaro is supplied with water by a spring which issues on 
the mountain slopes about 2000 feet above the sea, its temperature 
at 3 p.m. on August 3 being 54° Fahr., or about ten degrees cooler 
than the mean temperature of the air in the shade at that altitude. 

A similar spring is said to exist far up the mountain-side behind 
Caes-o-Pico; but it is not utilised by the villagers. At the head of 
a gully, some 500 or 600 feet above this place, there is a water- 
source which has been protected by masonry; but it seems to be 
only used for washing clothes. Here the water is derived from the 
drippings of cliff-faces on either side, the line of underground soakage 
being cut across by the gully, a circumstance which shows that in 
this eastern part of the island there is a large amount of fresh-water 
available. But lack of funds is the great obstacle, though a little 
enterprise, like that displayed by the inhabitants of Santo Amaro, 

K K 



498 



APPENDIX 



might provide several other of the coast villages with good water 
from the mountains. Dripping- cliffs, in particular, ought to be 
fairly common; and, since they afford a substitute for permanent 
springs, they might readily be utilised for this purpose. 

Note 37 (p. 358). 
Uncinia. 

It has been shown in Chapter XVI. that a few species of Car ex 
have probably crossed the Southern Ocean between the southern 
portion of South America and the Australian and New Zealand 
region. Considerable light is thrown on the possibility of this 
oceanic traverse by the distribution in high southern latitudes of 
another genus of the Caricoidece, namely, Uncinia, which is essentially 
a genus of these latitudes, since four-fifths of its species are there 
confined. 

The twenty-four species recognised in KiikenthaPs monograph on 
the Caricoidece (Pflanzenreich, 1909) are chiefly divided between the 
two widely sundered regions centering in the southern extreme of 
South America and in New Zealand. The two regions, however, are 
connected by a single species (U. macrolepis) found both in the 
southern island of New Zealand and in Fuegia; and they are in- 
directly linked together by the association in the intervening islands 
of Amsterdam and St. Paul of a New Zealand species, U. compacta, 
and a Fuegian species, U. brevicaulis (see Hemsley's Chall. Bot., III., 
159, 267). 

The species are about equally divided between the two regions, 
South America holding twelve and New Zealand thirteen species. 
Of the South American species six are confined to the southern 
portion extending from South Chile to Fuegia ; two are spread over 
much of the continent and reach in one case Central America ; one 
(U. jamaicensis) is confined to the tropical and subtropical portions 
of South America and to Central America and the West Indies, 
occurring often at high altitudes ; one is peculiar to Juan Fernandez ; 
and the last two are Antarctic species, extending in one case to the 
islands of Tristan da Cunha, St. Paul, and Amsterdam, and in the 
other to the South Island of New Zealand. Of the New Zealand 
species seven are restricted to that region and to the neighbouring 
small islands (Stewart, Antipodes, Chatham, etc.); and six extend 
to regions outside, namely, four to Australia and Tasmania, one to 
Hawaii, and one to Antarctic South America. This does not exhaust 
the limits of dispersal from the New Zealand centre, since among the 
species it has lent to Australia one has reached New Guinea and 
another Amsterdam and Kerguelen Islands. 

Two significant facts of distribution are here disclosed. In the 
first place, as regards the New Zealand group of plants Australia has 
no species of its own, every species occurring outside New Zealand 
and the small islands near being a New Zealand species, even in such 
distant localities as New Guinea and Hawaii. In the same way the 
southern part of South America is still the abode of ten out of the 



APPENDIX 



499 



twelve species found in that continent. The other fact is the absence 
of Uncinia from South Africa and from the African continent gener- 
ally. One might have looked for a representative on Table Mountain 
of a genus that has found a home on the isolated oceanic islands of 
Tristan da Cunha and St. Paul, etc., on either side of the continent. 

Yet the absence of Uncinia from South Africa is quite consistent 
with the usual behaviour of plants common to the southern part of 
South America and the Australian and New Zealand region. Hemsley 
gives a long list of plants (Chall. Bot., I., 52) illustrating the relation- 
ship of these two regions. A large number of flowering plants 
belonging to about ninety-three genera are included, the grasses 
being excluded. The mode of presentation does not admit of one's 
giving a precise numerical value to the results ; but it would appear 
that not over one-tenth of the species common to the South American 
and to the Australian and New Zealand regions occur in Africa. The 
indications of the cyperaceous species in this list alone are very 
suggestive. Out of a dozen species, belonging to six genera, all 
either occur both in South America (mainly in the south) and in the 
Australian and New Zealand region, or they are represented there 
by closely related forms; but only two of them are also found in 
South Africa. When dealing with Carex in Chapter XVI., it was 
pointed out that of twenty-one Australasian species found outside 
that region six occur in South America and only one in South Africa. 

It has already been remarked that the South American and New 
Zealand centres of Uncinia are still in touch with each other, since 
they hold a species in common and since species from the two centres 
meet in the intervening islands. The point we are now concerned 
with is the direction in which the inter-communication takes place ; 
in other words, the direction in which species of Uncinia would be 
likely to travel around high southern latitudes. The latitudes in- 
volved correspond approximately with the zone of the Westerly 
Winds, the belt of the Roaring Forties. Those who, like the writer, 
have performed the voyage before the strong Westerlies from the 
Cape to Australia in a sailing vessel and have watched the sea-birds 
following in the ship's wake for weeks together will be in a position 
to appreciate the influences at present determining the part taken 
by the bird in distributing seeds in these latitudes. These sea-birds 
travel around the globe in the belt of the Westerlies, and a case has 
been recorded where a Cape Pigeon (Daption capensis), marked by a 
ribbon around its neck, followed a ship for 5000 miles on its way 
home from Australia by Cape Horn (Coppinger's Cruise of the Alert, 
p. 18). Ever since 1888, when a letter of mine appeared in Nature 
(May 10) concerning this matter, I have held the view that South 
America has been a funnel from the Fuegian tip of which plants 
have through the ages been detached and carried ever eastward 
through the agencies of the westerly winds, the west-wind drift- 
current, and sea-birds. The efficacy of the sea-bird in these lati- 
tudes was brought home to me a few years before that date, when in 
1881 I found a seed, apparently sound, in the stomach of a Cape 
Pigeon caught by one of my mess-mates 550 miles east of Tristan da 
Cunha (Nature, XXVI., 12; Chall. BoL, I., 45; IV., 313). 



500 



APPENDIX 



It is to the sea-bird that we are obliged to appeal in the case of 
Uncinia, the hooked fruits of which, as is observed below, are well 
fitted for attachment to a bird's plumage. Yet Sir Joseph Hooker 
in the case of the flora of Kerguelen, whilst admitting that the winds 
which blow, as he remarks, from Fuegia to Kerguelen almost through- 
out the year, are the most powerful natural agents for distributing 
cryptogamic spores, rejects the agency of the bird. He finds it 
difficult to imagine how seeds could adhere to birds in their flight of 
4000 miles across a rough ocean, which is the traverse here implied 
(Phil. Trans. Roy. Soc, Vol. 168, 1879; see also Hemsley in 
Chall. Bot., I., 51). Yet the later observations of Moseley, Kidder, 
and others well illustrate how from their nesting habits in the islands 
of the Southern Ocean, such as Kerguelen, Tristan da Cunha, etc., 
albatrosses, petrels, and other sea-birds would be very likely to 
transport seeds in their plumage, a subject discussed in my work on 
Plant Dispersal (p. 276, etc.). This would certainly apply to the 
case of Accena, one of the most typical genera of these regions, 
the fruits of which, as Moseley observes, stick like burrs to 
feathers. 

Observation has shown that the hooked fruits of Uncinia may be 
as firmly entangled in a bird's plumage as those of Acoena. Morris, in 
a paper in Nature (Dec. 16, 1886) on the dispersal of plants by 
birds, takes the fruits of Uncinia jamaicensis to illustrate dispersal 
in a bird's feathers. This species, which has a wide distribution in 
Central America and in tropical and subtropical South America, 
grows on the highlands of Jamaica at altitudes of 5000 to 6000 feet. 
Migratory birds, as he states, on their way north and south between 
North and South America rest on these Jamaican uplands, and so 
exhausted are they that they have been easily caught with the 
hands. In two cases he found small migratory birds on these moun- 
tains, which were so completely entangled in the hooks of Uncinias 
that they were unable to escape. Large birds, he says, would break 
away ; but not without carrying off in their plumage a number of 
the fruits. The exserted hooked " rachilla " of the fruit is, he says, 
excellently adapted for catching firmly in plumage. 

Assuming that birds have thus distributed Uncinias over the 
Southern Ocean, there can be no hesitation in considering that their 
flight must nearly always have been east before the westerly winds. 
Under these circumstances one could scarcely look for any very 
definite arrangement of these and other plants concerned, since 
Fuegia would be ever supplying them to New Zealand and the 
intervening islands, and New Zealand would be ever returning them 
to Fuegia. Yet such an arrangement can be to a small extent 
detected. Hemsley, though he does not accept the implication, 
writes that " numerically there is a preponderance of Fuegian forms 
represented in Kerguelen and the other islands under consideration 
(Marion, Crozets, Heard), as opposed to what may be termed New 
Zealand forms " (Chall. Bot., III., 253). The endemic species of these 
islands, he adds, " exhibit, perhaps, a closer affinity with Fuegian 
than with New Zealand species." Yet, notwithstanding, he con- 
siders that " with all the facts before us there does not seem to be a 



APPENDIX 



501 



special affinity between the floras of Kerguelen, etc., and Fuegia, as 
distinguished from the flora of the zone generally." 

Perhaps fresh light may be cast on this matter if we regard the 
story of the differentiation of the genus within itself as indicated in 
Kukenthal' s pages. Of the two subgenera recognised by Clarke and 
himself, Pseudo-Carex and Eu-Uncinia, the first holds only a single 
species, Uncinia kingii, which is confined to Fuegia and from its near 
approach to Carex supplies a connecting link between the two genera 
(Kukenthal, pp. 25, 66, 109; Hemsley, Chall. Bot., I., 31). Carex 
microglochin, which belongs according to Kukenthal (pp. 11, 26) to 
Primocarex, the oldest of the four subgenera of Carex, is the species 
to which it is most closely related. It is an arctic-alpine plant of 
Eurasia and North America, and is associated with Uncinia kingii in 
Fuegia. The second subgenus, Eu-Uncinia, holds the other twenty- 
three species. It was subdivided by Clarke, and his opinion is adopted 
by Kukenthal, into two sections, Platyandrce and Stenandrw, the 
distribution of which offers the critical point in this discussion. 
The first holds six species, all of which are South American, one of 
them reaching the islands of Tristan da Cunha, Amsterdam, and 
St. Paul. The second section, Stenandrce, holds seventeen species, 
or about three-fourths of the species of the genus. Four of them 
are exclusively South American (South Chile and Fuegia). One 
(U. macrolepis) is common to Fuegia and the South Island of New 
Zealand. The rest belong to the New Zealand centre, seven being 
endemic, the others spreading to Tasmania, Australia, Amsterdam, 
and Kerguelen, and even to New Guinea and Hawaii. 

The situation thus revealed is this. Although the species of the 
genus are about equally shared between the two centres, South 
America and New Zealand, South America holds both subgenera and 
both the sections of the subgenus, Eu-Uncinia. On the other hand, 
the New Zealand centre holds only one subgenus and only one of its 
two sections, namely, Stenandrce; but it claims the majority of its 
species. The upshot of the discussion is that whilst South America 
was the original differentiating ground of the genus, New Zealand 
has been the principal centre of " formative power " in later times, 
the single section, which the last-named region holds, being the 
most vigorous and productive of the Uncinias. Some of the general 
arguments that would assign to Eu-Carex, the subgenus comprising 
two-thirds of the known species of Carex (793 in all), the last place in 
the development-scale of the genus (see Kukenthal, pp. 11, 25, 26), 
could be applied to the section StenandroB in the case of Uncinia, 
both of them holding the bulk of the species and displaying in their 
development of new forms as well as in their great range the highest 
degree of virility. 

Note 38 (p. 450). 

The fruiting behaviour of Atriplex portulacoides, L., at Salcombe, 

South Devon. 

This plant came under my notice only in one locality in the Sal- 
combe district, namely, on the shore of Blanksmill Creek, where it 



502 



APPENDIX 



formed in 1906 a single patch a few feet across. The following notes 
were made on it in that year. 

Jan. 17, in full leaf ; some stems bearing immature fruits. June 30, 
beginning to flower. Aug. 31, flowering copiously, also in early fruit. 
Oct. 5, foliage still abundant; in seed; but the nuts are soft and 
whitish and the albumen is creamy and not set, whilst the fully 
formed dark-green embryo seems almost escaping through the 
delicate membranous fruit- covering. Nov. 9, abundant healthy 
green foliage and abundant green fruit; the fruit still soft, but the 
green embryo has grown at the expense of the creamy albumen, 
though still within the fruit-coverings. 

Evidently the plant this year has been on the eve of vivipary. 
The albumen never hardened and there was no rest period. Since 
the plant appears to be most at home in the warmer climes of the 
Mediterranean, it would almost seem that in the northern part of 
its range it may endeavour to counteract the effects of colder climatic 
conditions by dispensing with the rest period of the seed. From this 
point of view the vivipary of the mangroves in the tropics might be 
regarded as due to their endeavour to accommodate themselves to 
climatic conditions cooler than those that once prevailed in those 
regions. 

Note 39 (Chapter XI). 
On recent observations in the Western Bahamas by Dr. Vaughan. 

The writer is deeply indebted to Dr. Vaughan of the U.S. Geo- 
logical Survey for his great courtesy in sending him some of his 
papers on the Bahamas and in replying to his numerous queries 
on the subject ; but unfortunately his letter came too late to enable 
its contents to be utilised in Chapter XI, which is concerned with 
the geology of the Turks Islands. The remarks below refer to 
points raised in that chapter under the pages indicated. 

The oolitic character of the grains of the O3olian formation or cal- 
careous sandstone of the Bahamas (p. 260). — In the first place, 
it should be noted that L. Agassiz, in his paper on the Salt Key 
Bank, long since remarked the occurrence of oolitic grains in the 
fine sand of the bank, which is covered by four or five fathoms of 
water. Dr. Vaughan has watched the growth of oolitic grains in 
the shoal-water muds of the Bahamian seas, muds that " only 
need induration to become oolitic limestones." The precipitation 
of the carbonate of lime is attributed to denitrifying bacteria, which, 
as shown by Drew and Kellerman, exist in enormous quantities in 
the surface ooze of the Florida and Bahamian shoals. These oolitic 
grains ultimately form the beaches and the dunes and the more or 
less compacted asolian rock. 

Comparison of the ceolian formation of the Bahamas and the 
Bermudas (p. 273). — According to Dr. Vaughan, although both 
are calcareous, the mechanical conditions of the Bermudian and 
Bahamian formations are very different. Whilst in the first case 
the deposits are composed of broken-up shells, tests of foraminifera, 
and occasional coral fragments, in the second case through chemical 



APPENDIX 



503 



precipitation in sea- water these materials have formed " nuclei " 
for the development of oolitic grains. 

The foundations of the ceolian rock or wind-blown oolite of the 
Bahamas (p. 262). — In reply to a question put by the writer, Dr. 
Vaughan states that in the western islands the wind-blown oolite 
rests on a foundation of marine oolite, and that in no instance did 
he find " really coral reef rock interbedded with the oolitic rocks." 
He adds that " after the (submarine) formation of the oolite, prob- 
ably during a period of uplift, considerable quantities of material 
were blown up by the wind and formed the dunes." These wind- 
blown materials gave rise to the more or less compacted aeolian 
rocks ; and it would seem to the present writer that a critical point 
of first importance would lie in the determination by borings and 
other methods of the relation of the level of the base of the wind- 
blown rock with reference to that of the sea. According to his 
view the junction of the wind-blown with the marine oolite would 
be found at or about the present sea-level; but if, as held by A. 
Agassiz, there has been a subsidence of 300 feet since the formation 
of the islands, it would be found far below that level. 

The non-existence in South Florida of the calcareous ceolian oolite 
of the Bahamas (p. 273). — It is a very significant fact that, as 
Dr. Vaughan has informed the writer, this formation does not exist 
in South Florida. Yet the islands of the neighbouring Bahamas 
from end to end of the great archipelago are composed of this forma- 
tion. There are extensive areas underlain by the marine oolite in 
South Florida, but no wind-blown oolite is known. The sands 
strewn over the interior of the peninsula, as well as those of the coast 
dunes, are mainly siliceous. 

The ocean-holes of the Bahama Banks (p. 258). — Dr. Vaughan 
tells me that A. Agassiz was undoubtedly correct in his inference 
of a considerable subsidence, which was based on the occurrence 
of these holes in the banks. With much diffidence I would suggest 
that their preservation during the ages that have since elapsed 
presents a difficulty, since it is not easy to perceive why they were 
not obliterated during the great destruction of the land-surface 
that, according to Agassiz, accompanied the submergence and by 
the accumulation of debris and the growth of marine organisms in 
later times. These ocean-holes are described as representing blow- 
holes, sinks,, caverns, canons, etc., in the original land-surface. 
Some of the smaller holes may have vertical sides with a sheer drop 
of ten fathoms and more, and one might imagine that the same 
submarine influences that produced them are still preserving their 
patency. 

A suggestion of the present writer for the comparison of the behaviour 
of sand-dunes of different mineral composition. — It may be that 
we cannot strictly compare the movement of sand in dunes formed 
of calcareous oolitic grains with that of sand in dunes derived from 
the disintegration of volcanic rocks, such as has been described in 
Note 34 of this Appendix on the moving sand-hills of the Ancon 
plains of Peru. A comparison of the two kinds of moving sand- 
hills on the lines adopted in that note may be suggested. In the 



504 



APPENDIX 



case of calcareous sand-dunes formed of oolitic grains, as in the 
Bahamas, we might obtain some interesting results, and it may be 
that under present conditions the behaviour of the calcareous sand- 
hills of the Bahamas would be very different from that of the medanos 
or moving sand-hills formed of volcanic rocks in Peru. In the 
case of the Bahama deposits we ought to know in what way the 
oolitic grains of the seolian rock differ as regards form and external 
markings from those of the beach sand and from those of the mud 
on the submerged banks. The effects of attrition ought to be very 
pronounced in the case of the grains of the wind-blown rock. Much 
depends on the answer to the query whether such effects of attrition 
display themselves ; and in this and in other connections concerned 
with these seolian rocks of the Bahamas we must be prepared for 
surprises. 

(In addition to the papers of Dr. Vaughan, named at the end of 
Chapter XI, may be mentioned a very interesting note comparing 
the formation of the Floridian and Bahamian oolites in the Journal 
of the Washington Academy of Sciences, May 19, 1913. The origin 
of these oolites is also discussed in papers of more recent date on 
the Floridian Plateau and on shoal-water samples from Murray 
Island (Australia), the Bahamas, and Florida, in publications 133 
and 213 of the Carnegie Institution of Washington, as well as in a 
paper on the geology of the Bahamas and Southern Florida in the 
Yearbook of the same institution for 1914.) 



GENERAL INDEX 



Noti. — Several subjects are worked up in this index, which, on account of the 
plan of the book, could not be treated connectedly in the text; for example, the 
sources of bottle-drift thrown upon the Irish coast and on the Carribean shores 
of Central America. 

Except where several references of importance are given, the figures in larger 
type indicate the pages where the subject is treated at length, or where the most 
important points are discussed. 



Acacia, 167, 168, 171; A. acuifera, 287; 

A. farnesiana, 166, 287 
Acaena, 294, 500 
Acer, 326 

Acrocomia, 3, 4, 11, 86, 91, 160 
Acrostichum squamosum, 370, 375, 380, 
425 

Adder -stones, name of stranded West 

Indian seeds, 21, 23 
Adeno carpus viscosus, 408 
iEolian rocks, in the Turks Islands and 

Bahamas generallv, 254-276, 452, 502- 

504 

Africa ; Carex and Sphagnum floras, 332- 
358, 341-347, 356; current-connec- 
tions, 294-312, 300-305, 311, 475- 
477, 478 ; Uncinia, 499 

West ; comparison of littoral flora 

with that of the West Indies, 83-95, 
141, 194, 207 ; bottle-drift, 49-53, 59, 
67-71, 76-81, 475-477. See Sierra 
Leone. 

East ; bottle-drift, 50, 300-305 

North ; bottle-drift on coast of 

Morocco, 51, 52, 53 

South ; bottle-drift, 63, 77 

Agassiz, A. ; on the formation of the 

Bahamas, 254-261, 269, 274-276, 503 ; 

on the early maps of the group, 264, 

275 

L. ; on the Salt Key Bank, 261, 274, 

276, 502 
Agrostis castellana, 370, 372, 386 
Agua do Pao, a mountain in San Miguel, 

Azores, 438 
Aiton, 361, 493 

Alacran Shoals, plants, 187, 188, 201, 231, 
240, 250 

Albatross ; in seed -distribution, 500 
Alcyonarian sea-shrubs, in the Scilly 
Islands and Norway, 21 

505 



Alder, name of Cono carpus erectus in the 

West Indies, 201 
Aleurites moluccana, 160 
Algaroba, 102 

Algarve (Portugal), introduction of 

Myrica faya, 434 
Allen, E. J., Physaliae on English beaches, 

29 

J. A., on distribution, 325 

Alligators, 102, 105, 107, 175; drifted to 

the Turks Islands, 487. See Crocodiles. 
" Alma Cummings " (derelict), its track, 

69, 72, 472 
Alnus maritimum (Conocarpus erectus), 

201 

Alternanthera, 85 
Amarantacese, 85 

Amazon; seed-drift, 7, 8, 13, 19, 39, 74, 
75, 81, 128, 129, 142 ; bottle-drift from 
off the estuary, 62, 67, 70, 71, 74, 75, 80, 
444, 445 : plants chiefly of the estuary, 
7, 128, 131, 133, 135, 141, 160, 212 

Ambrosia crithmifolia (A. hispida), 87, 
172, 279-283, 288, 291, 451, 452 

America, Central; recipient of seed-drift 
by the North and Main Equatorial cur- 
rents, 8, 72, 73 ; seed-drift on opposite 
coasts, 17, 19 ; bottle-drift from off the 
shores of Europe, 48, 53, 57 ; from the 
vicinity of the Canary and Cape Verde 
Islands, 57, 58; from between St. 
Paul's Pocks and the coast of Brazil, 
50, 61 ; from off the Amazon estuary, 
75; from between Hispaniola and the 
Turks Islands, 466; derelict from off 
Cape Hatteras, 50, 472 

North ; bottle-drift to Europe, 52- 

55, 66, 68; Carex and Sphagnum 
floras, 332-358 

South ; current-connections, 294- 

312, 297, 299, 310; Carex and Sphag- 



506 



GENERAL INDEX 



num floras, 332-358, 335-341, 356; 

Uncinia, 498-501 
American genera in Macaronesia, 408, 

410, 412, 413, 416 
Amsterdam Island; Sphagnum and 

Uncinia, 344, 346, 498, 501 
Amulets, West Indian drift-seeds as, 22, 

24 

Anacardium occidentale (Cashew-nut), 

28, 36, 173 
Anagallis filiformis, 480, 481 
teneUa, 371, 377, 379-381, 387, 

402, 417, 419, 425, 479 
Anchovy Pear. See Grias cauliflora. 
Ancon (Peru)$ See Medanos. 
Andira inermis (Angeleen-tree), 4, 11, 16, 

86, 88, 91, 92, 95, 150 
Andrews, E. C, on the Australian flora, 

171, 317-319, 322, 330 
Andropogon glomeratus, 451, 453 
Angeleen-tree* See Andira inermis. 
Annual Register, 277, 487 
Anona, 174-181; A. cherimolia, 177; A. 

glabra, 181 ; A. klainii, 181 ; A. muri- 

cata (Sour Sop), 177, 181 ; A. palustris, 

4, 5, 18, 86, 90, 174-181, 194; A. 

reticulata (Custard Apple), 177 ; A. 

senegalensis, 181 ; A. squamosa (Sweet 

Sop), 177 

Antarctica, as a centre of dispersion, 309, 
328, 330 

Antarctic latitudes (Southern Ocean); 

seed-distribution by sea-birds, 294, 

498-501 ; Carex and Sphagnum, 337- 

340, 348, 349; Uncinia, 498-501; 

bottle-drift, wreckage, and currents, 

295, 296, 299, 300, 306, 310 
Antidote Vine.- See Fevillea cordifolia. 
Antillean Stream, 10, 14, 19, 58, 62, 73, 

79, 463-469, 471, 481 
Antilles, Greater; bottle-drift, 56, 57, 61, 

72, 73, 442-445 
Lesser ; bottle-drift, 57, 58, 60, 

61, 62, 69, 71-75, 442-445 
Antipodes Island, 348, 498 
Antoine, 431 

Aquatic plants ; in Jamaica, 16, 104-107 ; 

in Azores, 371, 378-382, 387, 403, 405, 

407, 417, 420, 439 
Arabis albida, 411 

Arachis hypogsea; in European beach 

drift, 28, 29 
Araucaria, 294, 328 
Arbutus, 408 
Arcangeli, 405, 426, 437 
Arceuthobium oxycedri, 360, 370, 375, 

379, 386, 401, 426; distribution of 

genus, 426 
Arctic latitudes, bottle-drift, 484, 495 
Arenaria serpyllifolia, 411 
Argemone mexicana, 290 
Argythamnia argentea, 287 
Aridity and cold currents, 271, 272, 275 



Armeria ; maderensis, 411 ; maritima, 187 

Aroids; climbing, 16; arborescent, 455 

Arundo saccharoides, 105, 106 

Ascension Island; bottle-drift and posi- 
tion as regards currents, 60, 67, 70, 76, 
81, 443, 460, 474, 475, 482, 483 ; flora, 
459, 460 

Asplenium marinum, 492 

Astrocaryum, 6, 12-14, 25-27, 37, 38, 
86, 91, 181 

Atlantic, currents and bottle-drift, 46-82, 
475-477; drift-rates, 65-71; general 
results, 71 

North ; currents and bottle-drift, 

46-59; circulatory movements, 51, 
54, 55, 71, 72, 80, 471; bottle-drift in 
high latitudes, 484, 495; general 
results, 71. See Gulf Stream, North 
Equatorial, Guinea, and Counter 
Equatorial Currents. 

South ; current-system, 59, 60, 62 ; 

bottle-drifts, 59-64, 67, 69, 70, 71; 
current-connections with Indian and 
Pacific Oceans, 63. See Main Equa- 
torial, Brazilian, Guinea, and Counter 
Equatorial Currents and Amazon 
bottle-drift. 

Atlas, Great ; plants in the Azores, 405, 
408 

Atriplex portulacoides, 448-450, 501 

Australia ; current-connections and bottle- 
drift, 49, 60, 63, 140, 294-312, 297, 
309, 310 ; differentiation of flora, 228, 
229, 317-319; Carex and Sphagnum, 
332-358, 347-352, 357 ; Scsevola, 227- 
236; Acacias, 167, 171,319; Myrtaceje, 
317; Leguminosse, 318; Eucalyptus, 
318, 319; Uncinia, 498-501; as a 
source of wide-ranging littoral plants, 
171, 192, 207, 228, 229; drift-seeds in 
South Australia, 140, 164. See under 
West Australian Current. 

Avena marginata, 411 

Avicennia (genus), 309, 454 

nitida, 181; distribution, 86, 181, 

454 ; as a constituent of the mangrove 
formation, 4, 10, 15, 90, 100, 106, 108, 
109, 202, 203, 283, 289, 290, 452; 
represented in stranded beach-drift 
and floating estuarine drift, 10, 12, 15, 
17, 182, 446; mode of dispersal, 4, 18, 
86, 90, 182, 451, 452; effect of drying 
on germinating fruit, 182; viviparous 
habit, 4, 182 

Azevinho. See Ilex perado and I. 
azevinho. 

Azolla, 16, 105, 107 

Azores : 

Author's sojourn, 359; his ascents of 
Pico, 360; history of botanical 
investigation, 361, 385; heights of 
the islands, 364; conditions for 
forest-growth compared with those 



GENERAL INDEX 



507 



Azores (continued) — 

of Madeira and the Canaries, 365, 
385 ; profile of the mountain of Pico, 
365; bluffs of Ribiera grande, 366; 
extent of vegetation on Pico, 367, 
385 ; the zones of vegetation on Pico, 
367, 386; their comparison with 
those of Teneriffe and Madeira, 407- 
411, 415; prevailing climatic con- 
ditions of Pico, 371 ; snow on the 
mountain, 372; general account of 
the vegetation of Pico, 372, 387; 
the summit -plants of Pico, and. their 
comparison with those of Teneriffe 
and Madeira, 370, 372-374, 386, 411, 
416 ; vegetation of the upland moors 
of Pico, 376, 386; secondary cones 
of Pico, 378 ; weUs of Pico, 388, 496 ; 
lake-district of Pico, 378, 387 ; sanc- 
tuaries for plants on Pico, 374, 375, 
387 ; extensive Sphagnum region on 
Pico, 377. 
Bottle-drift on the Azores, 49-55, 64, 
68, 460 

Firewood in the Azores, 397, 398 
Notes on Azorean plants, 425 ; plants 
collected by Forster on Fayal, 491 ; 
coast plants of Azores, 218, 219, 384, 
388; uplands of San Miguel, 382, 
387; Terceira, 383, 387; species of 
Sphagnum in the Azores, 343, 478; 
Sargasso weed on Azorean beaches, 
485 ; list of works on the plants of 
the Azores, 439 
Proportion of native plants of Azores, 
389, 414; characters of the original 
forests, 391, 414, and the large size 
of the trees, 392, 414; large trunks 
buried in volcanic ashes, 393, 414; 
maximum size of existing trees, 395, 
414; causes of the destruction of 
the original forests, 396, 414 ; affmi- 
tiesof the native flora, 398-411, 415 ; 
distribution of characteristic native 
plants, 400 ; plant-stocking of the 
Macaronesian Islands, 411, 416; 
derivation of some plants from the 
Great Atlas, 405; relation between 
the differentiating and dispersing 
agencies, 399, 417, 438; modes of 
dispersal of Azorean plants, 417, of 
those of the woods, 418, 438, of 
aquatic and subaquatic plants, 420, 
439; of coast plants, 420, 439; 
of the plants of the moors, 418, 
438; the efficacy of winds in 
plant-dispersal, 422, 439; early 
cultivated plants of the Azores, 
397. 

Pumice on the beaches of the Azores, 
479 

West Indian seeds carried to the 
Azores, 27, 37, 122, 158, 181 



Babington, on Iceland beach-plants, 
187 

Baccharis dioica, 285, 292 
Bactris, 4, 13 

Bahamas, including the extreme south- 
eastern islands (Turks, Caicos, etc.) : 

Bottle-drift stranded on the islands, 
49, 51, 54, 56-58, 61, 62, 64, 71-73, 
79, 462-465, 470, 471, 477. 

Bottles dropped overboard in their 
vicinity or passing near them " en 
route," 14, 72, 463, 465, 466, 468, 
477. See Turks Islands. 

Climate, Aridity of, in past ages; 271, 
272 275. 

Flora,' 11 7, 168, 192, 198, 202, 210, 224, 
225, 284, 290. See Turks Islands 
flora. 

Geology, 254-276 (see Turks Islands), 
502-504 ; Bahama Banks, 254, 255 ; 
former land connections, 272, 273; 
evidence of change in old charts, 264, 
275 

Bahia, bottle-drift, 71 
Bain, on Dracaena draco, 489 
Baker, E. G., on Sacoglottis amazonica, 
137 

Ball, J., on plants of the Great Atlas, 

405, 408, 439 
Baltic coasts, West Indian seeds, 36 
Barbados olive, 286 

Barringtonia, 5, 168, 175, 213, 214, 243, 
454 

Barrow, on drift-wood stranded in high 
northern latitudes, 35, 45 

Batatas acetosaefolia, 217 

Bates, H. W., on Amazon drift, 75, 128 

Batis maritima, 101, 106, 108, 283, 290- 
292, 451-453, 478 

Bauhin, C, on the seeds of Ipomcea 
tuberosa, 32, 42, 161-163 

J., on the fruits of Sacoglottis 

amazonica, 42, 137 

Beach-drift, West Indian; sources, 1, 3, 
18; sorting process and fine drift, 6, 
241 ; general description and char- 
acters, 2, 6, 18 ; list of plants supplying 
it, 5, 6 ; contrasted with West Indian, 
Indian Ocean, and tropical Pacific 
beach-drift, 5, 18; selection of the 
Turks Islands for the study of its 
oceanic transport, 8, 14, 19 ; compari- 
son of beach-drift on the Pacific and 
West Indian coasts of tropical America, 
17, 19. See also under Jamaica, 
Trinidad, Turks Islands. 

Beach plants of West Indies and West 
Africa compared, 87, 88, 91-95 

of West Indies. See under Littoral 

plants. 

sand-rock, 263 

Becher, A. B., on bottle-drifts in the 
North Atlantic, 46, 50, 57, 66, 81 



508 



GENERAL INDEX 



Beirao, C. M. F. da, concerning plants 
from the Azores, 364, 434, 439 

Bentham, on plant-distribution, 324, 327, 
329, 330, 354; Acacia farnesiana, 166, 
171; Cassytha, 191, 193; Chrysobala- 
nus icaco, 196; Dioclea reflexa. 131; 
Dodonsea viscosa, 206; Mucuna, 121, 
459 ; St. Helena flora, 460 ; Thespesia 
populnea, 244 

Bent-stone. See Buesteen. 

Berghaus, H., on bottle-drift, 46, 81 

Bermuda; its stranded bottle-drift, 49, 
51-54, 62, 65, 466-471; its relation 
to the currents, 466-471 ; West Indian 
seed-drift on its shores, 38, 139, 158, 
468 ; flora, 146, 204, 466; geology, 259, 
273, 502; supposed continental con- 
nection, 466 

Beta maritima, 384, 404, 420, 447, 448, 
450 

vulgaris = Beta maritima. 

Bibliographies, or lists of works quoted : 
botanical works, at the beginning of 
volume; West Indian seed-drift on 
European shores, 42 ; bottle-drift, 81 ; 
geology of the Turks Islands and 
Bahamas, 276; current-connections in 
southern hemisphere, 312 ; concerning 
plant -distribution, 330; plants of the 
Azores, 439 

Bigbury Bay (South Devon); West 
Indian seed-drift, 28, 134 

Birds; as seed-dispersers, 32, 175, 192, 
198, 252, 291, 294, 354, 418-^22, 435, 
437, 450, 454, 489, 499, 500 ; sea-birds, 
32, 294, 421, 499, 500; pigeons, 175, 
192, 198, 252, 418, 435, 454, 489; 
parrots, 175; wild ducks, 420 

and Currents associated in seed- 
dispersal, 192, 230, 232, 252 

migration to Africa, 354; to the 

West Indies, 500 

Biscay, Bay of; stranded bottle-drift 
49, 52-56. (At least two -thirds of the 
bottles included in the tables as re- 
covered on the coasts of France and 
Spain would be placed under this head. ) 

Black River. See Jamaica. 

Blechnum spicant, 371, 374, 377 

Blue Hole. See Jamaica. 

" Blue Jacket," figurehead washed ashore 
at Fremantle, 296, 298 

Boa constrictor, stranded on St. Vincent, 
486 

Boid, on the ascent of Pico, 361, 372, 439 
Bolle, on Juniperus oxycedrus in the 

Canaries, 408 
Bontia daphnoides (Barbados olive), 198, 

286 

Boobies, swallowing seeds of Guilandina 

bonducella, 32 
BoodJei on the character of the timber 

of a buried Azorean tree, 395 



Borago officinalis, 491 

Borgesen, on West Indian seeds stranded 
on the Faroe Islands, 35, 42 

Borrera thymifolia, 285, 286, 288 

Borrichia arborescens, 87, 183, 194, 202, 
279-283, 286, 289-291, 451, 452 

Bottle-drift : 

Chapter dealing with, 46-82; drifting 
rates, 64-71; summary, 78; tables, 
52, 53, 57, 61, 65, 66, 67, 71, 462, 464, 
466, 475; history of the investiga- 
tion and sources of materials, 46, 
47; the value of bottle-drift data, 
48 ; proportion of recoveries, 48, and 
the associated difficulties, 49 ; tracks 
of bottles thrown over together, 
49; divergent tracks of derelicts 
and casks, 50 
Illustration by bottle-drift of the 
distribution by the equatorial cur- 
rents of seed-drift over the West 
Indies, 72 ; the burden of the Main 
Equatorial current, 73; the island 
of Trinidad as a centre of seed-drift 
dispersal, 74; the transport of 
Amazon drift to the West Indies, 
Florida, and Europe, 75 ; the balance 
of the account between the Old and 
the New World, 76; drift carried 
by currents round Cape Horn, Cape 
Agulhas, and the North Cape, 78 
Surface-circulation of the North At- 
lantic, 51 ; the passage of bottle- 
drift from the West Indies to 
Europe, 52, and from Europe and 
North-West Africa to the West 
Indies, 58 
The currents of the South Atlantic, 59 ; 
the transport of bottle-drift in the 
Main Equatorial Current, 60; the 
South Equatorial and the Brazil 
currents, 62; the current-connec- 
tions of the South Atlantic with the 
Indian and Pacific Oceans as indi- 
cated by bottle-drift, 63 
The difficulties connected with the 
drift-rates of bottles across the 
Atlantic, 64; the drift-rates from 
the West Indies to Europe, 65, 66 ; 
from Europe to the West Indies, 
66, 67, 68; from tropical Africa to 
Brazil and the West Indies, 67, 69; 
from off the Amazon estuary to 
Florida, 70, and in the Brazil current, 
70 ; general results for the Atlantic, 
71 

See Africa, Amazon, America, Ant- 
arctic latitudes, Antilles (Greater and 
Lesser), Antillean Stream, Arctic 
latitudes, Ascension, Atlantic, Aus- 
tralia, Azores, Bahamas, Bermuda, 
etc. 

Boulogne, West Indian drift -seed, 28 



GENERAL INDEX 



509 



Bourbon, Island of; Carex and Sphag- 
num, 343-346 
Bowlesia, 412 

Bracken. See Pteris aquilina. 

Brand, J., on turtles stranded on the 

Shetland Islands, 40, 42 
Brandis, D., on Arceuthobium oxycedri, 

426 

Brazil, bottle-drift, 8, 61, 63, 69-71, 76, 
474, 475 

Brazilian Current, 60, 62, 63, 70, 80, 89 

Britton, N. L., on Bahamian and Jamai- 
can plants, 9, 106, 205, 284 

Broadway, W. E., on Entada scandens 
in the West Indies, 118 

Brooke, A. de Capell, on West Indian 
seeds and mahogany baulks cast on 
the Norwegian and Orkney coasts, 25, 
34, 35, 40, 43 

Brotero, on Myrica faya in Portugal, 434 

Brown, A. Samler ; no reference to West 
Indian seed-drift on the Canaries, 39 ; 
comparison of the slopes of the cones 
of Pico and Teneriffe, 366; Juniperus 
oxycedrus on Palma, Canaries, 408; 
ascending air-currents on the Peak of 
Teneriffe, 425 ; Mesembryanthemum in 
Canaries, 449; submarine freshwater 
springs off the Canaries, 497 

C. S., on Azorean plants, 218, 359, 

364, 384, 385 

R., on a Guilandina seed on the 

Irish coast, 30 

Miss S., on the buried Junipers of 

the Azores, 394 

Brownson Deep, 258 

Bruguiera, 309 

Buch, Von, on the zones of vegetation of 

Teneriffe, 407 
Buchenau, on the means of dispersal of 

Juncus and Luzula, 419 
Bucida buceras, 16, 17 
Buesteen (Bent-stone), 23, 27, 208, 209 
Bulimoid shells in aeolian rock in the 

Turks Islands, 260 
Bullar, H.\, on the Azores, 361, 397, 

J. / 398, 440 

Buller, A. H., on the falling rate of 

spores, 355, 423 
Bullock, on seeds of Entada scandens on 

Orkney and Norwegian beaches, 34, 36 
Buoyancy of seeds and seed-vessels ; 

comparison of behaviour in fresh water 

and sea-water, 117, 123, 124, 132, 139; 

investigations of Lloyd Praeger, 473 
Results of experiments ; West Indian 

littoral and estuarine plants, 86, 87; 

species of Anona, 177; Cakile, 189; 

Scaevola, 236; Tournefortia, 251. 

Other results, 123, 169, 173, 174, 180, 

183, 190, 192, 199, 204, 207-209, 218, 

221, 223, 225, 237-239, 242, 247, 421, 

428, 447, 449, 450, 456-458. (For 



the principles involved, see under 
Littoral plants and in my previous 
work on Plant -Dispersal.) 
Bur kill, I. H., concerning Acacia farnesi- 
ana, 171, and Thespesia populnea, 
246 

Burnt-bush. See Euphorbia vaginulata. 
Bussu palm, Manicaria saccifera, 128 
Butter-nut. See Caryocar nuciferum. 
Button-tree. See Conocarpus erectus. 
Byronia, 429 
Bystropogon, 410, 412 

Cabarita River. See Jamaica. 
Cabeza Norte (Pico, Azores), 378 
Cabral, the Portuguese navigator, 396 
Cacoon, 205. See Cocoon. 
Cactacese, 168 
Cactus. See Opuntia. 
Caesalpinia, 456. See under Guilandina. 
bonducella, 139* See Guilandina 

bonducella. 
Caicos Islands ; bottle-drift, 56, 462-465, 

477; flora, 224, 284, 286, 287, 290; 

banks on which they lie, 255-258, 290. 

See Turks Islands and Bahamas. 
Cakile, 87, 184H89, 219, 282, 288, 291, 

384, 404, 407, 421, 427, 451, 452 
Calabash. See Crescentia. 
Calabash-tree. See Crescentia cujete. 
Californian current and climate, 272 
CaUitriche in the Azores, 371, 378, 382, 

387, 402, 417, 420 
Calluna vulgaris (Ling); in the Azores, 

370-374, 376, 377, 379, 383, 386, 387, 

398, 402, 411, 427 ; means of dispersal, 

417, 419, 422, 425 
Calonyction album, 221, 452; synonym 

of Ipomcea tuba, q. v. 
Calophyllum, 175; C. calaba, 11, 12, 155, 

215; C. inophyllum, 155, 156, 454 
Calotropis procera, 290 
Cambage, R. H. ; on Acacia farnesiana 

and other Australian plants, 170, 171, 

318, 319, 330 
Campanula, in the North Atlantic islands, 

428 

vidalii, 385, 404, 407, 413, 427, 

428 

Canadas (Teneriffe), 408, 411 
Canarina, 327 
Canarium, 454 

Canary Islands ; stranded bottle-drift, 
48, 52-54, 56, 69, 483, 484; bottles 
cast overboard in the vicinity, 57, 66, 
67, 68; West Indian seed-drift, 38; 
shore plants, 448 ; flora compared with 
those of the Azores and Madeira, 365, 
368, 369, 385, 398-416; history of 
the plant -stocking, 411-413, 416. See 
Teneriffe. 

Canavalia, 133 ; C. obtusifolia, 5, 12, 17, 
87, 92, 189, 283, 291, 451, 452, 454 



510 



GENERAL INDEX 



Candolle, A. de, 76, 89, 120, 152, 159, 166, 

172, 193, 196, 207, 216, 362, 480 
Cannaceae, 315 

Cape of Good Hope and Cape Agulhas; 
doubling the southern extreme of 
Africa by seed and bottle-drift, 39, 62, 
63, 78, 81 

Cape Horn, doubled by bottle-drift, 63, 
78, 81 

Cape-pigeon (Daption capensis), as a seed- 

disperser, 499 
Cape Race. Ste under Newfoundland 
bottle-drift. 

Vorde Islands ; bottles dropped over 

in vicinity, 57, 6/, 69; Acacia farnesi- 
ana, 170; Cassia fistula, 155 
Carapa, 141, 228, 309 ; C. guianensis, 3-5, 
11-13, 18, 86, 90, 141; C. moluccensis 
and C. obovata, 141-143 
Cardot, J., the Mosses of the Azores, 440 
Carex compared with Sphagnum : 

Influence of the divergence of the 
continents on their distribution, 
332-358 ; both respond to the same 
law, 332; comparison of the East 
and West Hemispheres in the north, 
335; connections of the South 
American Carex and Sphagnum 
floras, 335 ; the stream of arctic and 
subarctic species down the Andes 
to Cape Horn, 337 ; the Carex 
and Sphagnum connections between 
South America, Africa, and the 
Australian and New Zealand region, 
339; the isolation of Africa, 341, 
342; the outside connections and 
sources of the African Peat-mosses 
and Carices, 344-346; Sphagnum 
and Carex in Australia and New 
Zealand, with their Asiatic and South 
American connections and the bridg- 
ing over of the gap in Malaya, 347- 
353; the insular factor, 343; the 
distribution of the Carices by birds 
and of the Peat-mosses by winds, 
354; summary, 355. See also Africa, 
South America, Australia, etc. 
Carex acutiformis, 342, 345, 346; brun- 
nea, 345, 350; breviculmis, 350, 351; 
canescens, 338, 339, 352; cernua, 345, 
346, 349; darwinii, 340, 349, 352; 
divisa, 342, 345, 346; extensa, 342, 

345, 346; flava {see note below), 371, 
380, 381, 387, 402, 420 (included here 
amongst the subaquatic plants, though 
it is also abundant in the wet moors); 
lagopina, 351, 352; macloviana, 338, 
339; microglochin, 338, 501; ceded 
{see note below), 339, 341, 345, 346, 
349, 351, 352; ceded, var. cataractae, 

346, 351; pseudo-cyperus, 339, 342, 
351, 352 ; pumila, 339, 340, 351, 352 ; 
stellulata, 351, 371, 375, 378, 387, 403 



(its fruits float for a year and more 
and occur in the floating drift of ponds ; 
the plant's name should be associated 
with Carex flava on p. 420); trifida, 
340, 349, 352 ; vulpina, 342, 345, 346. 
(Single references to many other species 
will be found on pp. 338-352.) 

Note. — Carex ceded, regarded by 
Bentham and Hooker as a form of the 
Linnean species, C. flava, is separated 
by Kukenthal. Both are European 
and North American; but C. ceded, 
in the form of var. cataractae, extends 
to the southern hemisphere (Chile, 
Patagonia, South Africa, Tasmania, 
New Zealand). 
Caribbean Sea; traversed by bottle- 
drift and seed-drift brought by the 
equatorial currents from off the West 
African coasts, the Amazon estuary, 
Brazil, the Guianas, the Orinoco, etc., 
58-61, 73, 75, 444, 445; bottle-drift 
from the Caribbean Sea to Europe, 59, 
76 ; mingling in this sea of drift brought 
by the north and main equatorial 
currents from African and South 
American waters, 62, 73 
Carreiro, Bruno T., on the Azorean flora, 

359, 364, 385, 427 
Carthamus tinctorius (Safflower), 492 
Caryocar nuciferum (Butter-nut), 28, 30 
Cashew-nut. See Anacardium occiden- 
tals 

Casks, drifted by currents, 50, 76, 81, 299, 
481 

Cassia fistula, 6, 11-13, 28, 36, 152; C. 

grandis, 4, 11, 13, 16, 152 
Cassytha, 171, 207; C. filiformis ( = 

americana), 87, 92, 191 
Castillo, Drake del; on Pacific Island 

plants, 157, 171 
Catesbcea, 287 

Catesby, M. ; on Genipa clusiifolia, 210 ; 
on the Manchineel of the Bahamas, 
286 ; on the iguanas of the Bahamas, 
487 

Cattegat, fruits of Calluna vulgaris, etc, 

blown across, 425 
Cattle, spreading the seeds of Acacia 

farnesiana, 169, and those of Pithe- 

colobium saman (Morris in " Nature," 

March 15, 1888). 
Cauliflory, 147, 211 

Cayman Islands; seed-drift and bottle- 
drift brought by the equatorial currents, 
8, 61, 76, 130, 145 ; electric -light bulbs, 
165; Guilandina, 138, 456; Cakile, 
186; Cassytha, 192; Coccoloba uvi- 
fera, 197; Conocarpus erectus, 201; 
Ipomcea carnosa, 218, and I. tuba, 221 ; 
Mammea americana, 145; Morinda 
royoc, 225 ; Sophora tomentosa, 237 ; 
Suriana maritima, 240; Tournefortia 



GENERAL INDEX 



511 



gnaphalodes, 250 ; Vigna luteola, 251 ; 
Passiflora cuprea, 289; Dodonsea vis- 
cosa, 206 

Ceara (Brazil), bottle-drift, 8, 76, 130 
Cedar, Cedro. See Juniperus oxycedrus. 
Cedrela odorata, 111 
Cedronella, 410, 412 

Cenchrus echinatus, 282, 291 ; C. tribu- 

loides, 85, 451-453 
Cerastium tetrandrum, 411 
Ceratophyllum demersum, 16, 104, 105, 

107 

Cerbera odollam, 5, 168, 454 
Chaparral scrub, 168, 169, 229 
Charms, West Indian drift-seeds as, 22, 24 
Chastenet-Puysegur, De; old chart of 

some Bahama shoals, 264 
Chatham Islands ; Carex and Sphagnum, 

348, 349, 352; Uncinia, 498; cask 

drifted from the Macdonald Islands, 

299 

Chaves, F. A., concerning the Azores, 

359, 364, 365, 394, 396, 440 
Cheeseman, T. F., 171, 220, 246; on New 

Zealand weeds, 391 
"Cherokee," s.s. ; bottles thrown over- 
board from, 49, 65, 465, 467 
Chile, North; influence of Humboldt 

Current on climate, 271, 272, 275 
Chimborazo forests, 212 
Christ, D. H., on the Canarian flora, 406- 

408, 412, 440, 487 
Chrysobalanus, 83, 181, 193-196, 204, 

326; Chr. pellocarpus, 193 
icaco (Coco-plum), 5, 12, 87, 92, 

151, 179, 181, 193, 197, 205, 207 
Chrysodium vulgare (Swamp Fern), 105 
Cladium, 179, 455 

Clarke, C. B., on Ipomoea kentrocaulos, 
161 

Claussen, P., on West Indian seeds on 
Scandinavian beaches, 21, 23, 34, 35, 
41, 43 

Claw-grass, 453 

Clerk, W., on a West Indian seed from 

the Orkneys, 163 
Clerodendron, 175 
Clethra, 408, 410, 412 
Climate, aridity and cold currents, 271, 

272, 275 

Clusius (De l'Escluse), concerning West 
Indian drift seeds, 20, 32, 41, 43, 45, 
137, 161, 162 

Coccoloba, 197-200; C. laurifolia, 198 

uvifera (Seaside-grape); general 

treatment, 197-200; distribution, 87, 
197; station, 109, 116, 168, 194, 197, 
198, 200, 206, 210, 237, 244, 279, 283, 
286, 288, 289 ; means of dispersal, 87, 
94, 195, 198-200, 291 ; fruits in beach- 
drift, 5, 12, 198, 446 

Cockayne, on Dodonaea vi^cosa in New 
Zealand, 207 



Cocoon, 16, 30, 31, 34. See Entada 

scandens; 
Coco-plum. See Chrysobalanus icaco. 
Cocos nucifera (Coco-nut), 28, 29, 35-37 
Codeso (Adenocarpus viscosus), 408 
Coix lachryma, 106 
Cole, Grenville, on dune sand, 495 
Colon, beach drift, 6, 13, 14 
Colubrina, 200; C. asiatica, 5, 85, 87, 

92, 200 

Columba livia, in Azores, 418; C. 

palumbus, 418 
" Columbian Navigator." See Purdy. 
Commelyna, 106, 107 
Composite, dispersal by winds, 424, 425, 

439 

Congo, a source of seed-drift for the New 
World, 39, 74, 81 

Conifers, Mesozoic, 328 

Conocarpus erectus (Button-tree) ; general 
treatment, 201; variety, 202, 279; 
distribution, 87, 95, 201 ; station, 5, 10, 
105, 109, 168, 197, 200, 201-203, 206, 
244, 279, 280, 283, 289, 451, 452; dis- 
persal by currents, 87, 92, 93, 95, 203, 
204, 291, 452 ; in beach-drift, 5, 12, 17 

Convolvulus acetossefolius, 217 ; C. sol- 
danella, 217, 220, 294, 307, 308, 311 

Coppinger, Dr., on the long flight of the 
Cape-pigeon, 499 

Corals ; floating, 164 

Corchorus hirsutus, 278, 280, 286, 291, 
446, 478 

Cordeiro, old writer on the Azores, 393 
Cordia, 175 

Cornwall ; West Indian seeds on beaches, 
28, 45, 123 ; Cakile, 186, 188 

Cotula ; dispersal by sea-birds, 294 

Cotyledon umbilicus, 422 

Coutinho, A. X. P., Cape Verde plants, 
170, 449, 488 

Cow-itch (Mucuna pruriens), 457, 458 

Cozumel Island (Yucatan), bottle-drift, 
466 

Crantz, on drift-wood in high northern 

latitudes, 45 
Crassulacese, in Canary Islands, 408 
Crepis virens, 492 

Crescentia, 145-150; gourds probably 
carried to European shores, 25, 26, 36, 
146 

cucurbitina (Paki), 3, 11, 13, 15-17, 

86, 91, 145-150 
cujete (Calabash-tree), 3, 11, 13, 

15-17, 86, 91, 145-150 
Crinum, 3, 15, 16 

Crithnum maritimum, 384, 388, 404, 418, 

421, 448, 449 
Crocodiles, stranded on Keeling Atoll, 

303, 486. See Alligators. 
Crospunk, the Hebrides name for Entada 

scandens, 25 
Croton hjalmarssonii, 285 



512 



GENERAL INDEX 



Crudya, 83, 84, 204, 206, 326 ; Cr. spicata, 

3, 16, 86, 90, 106, 204 
Crueger, Dr., on Sacoglottis amazonica, 

134 

Cryptogams. See Spores. 

Cuba; seed-drift brought by the equa- 
torial currents, 8; bottle-drift, 52, 56, 
58, 61, 463, 466; forest-trees, 112, 117, 
215; submarine fresh-water springs, 
497 

Cucurbita, 145 ; C. lagenaria, 146 
Culcita fern. See Dicksonia culcita. 
Currents, as illustrated by bottle-drift. 
See under Bottle-drift, Atlantic, Aus- 
tralia, Equatorial Currents, Gulf 
Stream, Indian Ocean, Pacific Ocean, 
etc. 

(cold) and aridity, 271, 272, 275 

Cycas circinalis, 5 

Cyperacese, 105, 106, 109, 353 

Cyperus, 15, 353; C. brunneus, 85, 278- 
281, 291, 451, 453; C. compressus, 
491 ; C. elatus, 105, 106 ; C. esculentus, 
491, 492 

Dabney, American Consul-general in the 

Azores, 362, 372 
Dahl, F., on the arctic centre of dispersal, 

325 

Dana, J. D., Bahamian geology, 255, 262, 
263, 276 

Daphne; dispersal by birds, 417, 418; 

D. gnidium, 405 
laureola, 370, 374, 375, 386, 392, 

401, 405, 428 
Daption capensis (Cape-pigeon), 499 
Darrell, J. H., on Bermudian plants, 

197 

Dartmoor vegetation, compared with that 
of the moors of Pico, 371, 376, 386 

Darwin, C. ; petrels of St. Kilda swallow- 
ing West Indian drift-seeds, 32 ; West 
Indian drift-seeds on the Azores, 37, 
122 ; plants of Keeling Atoll, 170, 448 ; 
coral reef theory, 255; dispersal of 
plants from the north, 327 ; Darwinian 
evolution, 319, 322 

Datura stramonium, 290 

Daussy, on bottle-drift, 46, 69, 81 

Davey, F. Hamilton, on seeds of Entada 
scandens on the Cornish coast, 28 

Davis, Ains worth, quotation cited con- 
cerning currents, 39 

Strait; bottle-drift, 55, 79, 484, 

496; casks from a wrecked ship, 50. 
See Greenland. 

Dayssy. See Daussy. 

Deane, H., on the Tertiary flora of 
Australia, 318 

Debes, L. J., on the occurrence in the 
Faroe Islands of the seeds of Entada 
scandens, 21, 23, 33, 34, 41, 43 

Decaisne, J., on Mucuna pruriens, 458 



Deffarges, M., bottle-drift on the Chilian 

coast, 300 
De l'Escluse, 20. See Clusius. 
Denmark; West Indian seeds on the 

coast, 27, 36, 37 ; bottle-drift, 53 
Derelicts and currents, 48, 50, 68, 69, 72, 

472, 473 

Descourtilz, on Calophyllum calaba, 156 

Desmanthus, 326 

Deutsche Seewarte, bottle-drift, 47, 64, 
66, 74, etc. See under Schott. 

Devonshire; seeds and fruits from the 
West Indies and elsewhere in the 
beach-drift, 28-30, 123, 134; pelagic 
organisms stranded, 29; Cakile mari- 
tima, 185, 188 

Dicksonia culcita, 370, 375, 380, 382, 
383, 428 

Dieffenbachia seguine (Dumb-cane), 107 
Differentiation theory, 313-322, 323, 329 
" Difficult " plants. See Problem plants. 
Dildo, name of a species of Opuntia, 278, 
287 

Dimorphandra mora, seeds in beach- 
drift, 12, 13 

Dioclea, 133; D. guianensis, D. pana- 
mensis, D. violacea, 132; D. reflexa, 
4, 7, 11-13, 25, 26, 33, 34, 86, 91, 130, 
455 

Dioscorides, on the small Acacia, 172 
Distribution ; its controlling factors, 323- 

330 ; discontinuity, 83, 94, 326, 330. 
Dixon, C, on Brazilian drift seeds in the 

Fulmar petrel, 32 
Dodonsea, 171, 193 

viscosa, 86, 92, 109, 198, 206, 237, 

286, 288, 291; variety, D. burmanni, 
109, 206 

Dolichos urens (= Mucuna urens), 32, 35 

Dondia, 453 

Donkey-eye bean (Mucuna urens), 458 
Dracaena aurea, 487-489 ; D. ombet, 488 

draco (Dragon-tree), 408, 410, 412, 

487 

Drepanocarpus lunatus, 11, 86, 88, 90, 
159 

Drew, on denitrifying bacteria, 502 
Drift-wood, in high latitudes in the North 

Atlantic, 35, 40, 45 
Dripping cliffs in the Azores, 497, 498 
Droseracese, 315 

Drouet, H., on the Azorean flora, 359, 
363, 368, 382, 383, 385, 394, 418, 428, 
432, 435-437, 440 

Druce, G. C, on Campanula vidalii, 427; 
on other Azorean plants, 364, 434, 440 

Drude, O., on southern floras, 294 

Ducks, Wild, as seed-dispersers, 420 

Dumb-cane, 107 

Dwarfing of trees and shrubs; in the 
Azores, 367, 373, 374, 382, 386, 387, 
428^32, 437; in the Turks Islands, 
202, 279, 283, 446 



GENERAL INDEX 



513 



Dyer, W. T. Thiselton ; theory of centre 
of dispersion in the north, 323-330, 
332; evidence supporting it in this 
work, Anona, 181, Chrysobalanus, 181, 
196, Cakile, 187, Morinda, 226, Ximenia, 
253, Carex and Sphagnum, 353 

Eagle-stones, Norse name for West Indian 

drift seeds, 21 
Easter Island plants, 156, 246 
Ecastaphyllum in Turks Islands drift, 

genus doubtful, 111 
brownei, 5, 11, 12, 14, 17, 87, 88, 

92, 95, 159, 194, 197, 207, 244 
Echites, 287 
Echium, 408 
Ecuador : 

Beach-drift, 17, 145, 182, 190, 209; 
beach flora, 191, 203, 227; infiltra- 
tion of sea-water landward, 101 ; 
Rhizophora, 99 
Guayas or Guayaquil River; floating 
drift in the estuary, 3, 17, 145, 179, 
182, 209, 212, 222, 252; vegetation 
of estuary, 99, 178, 180, 222; 
salinity, 100, 180 ; underflow of sea- 
water in the estuary, 102 
Eggers, von, on West Indian plants, etc., 

98, 201, 203, 217, 227 
Elaeocarpus, 489 

Electric -light bulbs in beach-drift, 165 

Elliot, G. Scott ; on Cassytha filiformis, 
192 ; on Juniper growth, 430 

" Ely " (whaler), drift of a cask, 299 

Enallagma cucurbitina, 147 

England; bottle-drift, 52, 53; West- 
Indian drift seeds, 26, 28, 45, 123, 134 

Engler, A., southern floras, 294 

English, T. M. Savage; seed, bottle, and 
other drift on the Cayman Islands, 8, 
76, 130, 145, 165; Ipomcea acetosse- 
folia, 218; Sophora tomentosa, 237; 
Passiflora cuprea, 289 

Entada, 83, 118, 120, 133; E. poly- 
stachya, 118 

scandens seeds (Cocoon) ; general 

treatment, 86, 91, 117 ; in West Indian 
beach-drift, 4, 6, 11-13, 17, 117, 118; 
in European beach-drift, 22-28, 30-36, 
42, 45 ; in Azorean beach-drift, 37, 38 ; 
in river-drift, 4, 119; drift seeds used 
as snuff-boxes in Europe, 25, as tinder- 
boxes in the Hebrides, 25, and for 
medicinal purposes, 24; superstitions 
concerning the drift seeds in Europe 
and the popular names given to them, 
21-25 

Epilobium ; dispersal by winds, 423-425, 
439 

Equatorial currents of the Atlantic : 
Counter Equatorial, 59, 77, 89, 91, 93, 
94, 235, 301, 476. See under Guinea 
current. 
L L 



Main Equatorial; differentiated from 
the South Equatorial, 60, 79, 474; 
indications of bottle-drift, 8, 58, 59- 
62, 67, 69-76, 79, 80, 442-446; as 
a carrier of seed-drift, 7, 8, 72-78, 
81, 84-89, 94; bearing Amazon 
bottle and seed drift to the West 
Indies, 7, 8, 70, 75, 76, 81, 444-446; 
carries to the West Indies the sweep- 
ings of both sides of the South 
Atlantic, 73, 74, 81; mingling of 
its drift with that of the North 
Equatorial in the Caribbean Sea, 62, 
73, 81 

North Equatorial; indications of 
bottle-drift, 51-60, 57-59, 67, 69, 
71, 72, 73-76, 79, 80 

South Equatorial; 59, 60, 62, 80, 474. 
See above under the main current. 
Equatorial currents of the Indian Ocean ; 

indications of bottle-drift, 301-307, 

311 

Equatorial currents of the Pacific Ocean ; 
indications of bottle-drift, 297, 298, 
310 

Erica arborea, Canarian and Madeiran 

Tree-Heath, 406-408, 410 
— — azorica, Azorean Tree-Heath, 369, 

370, 373-379, 382, 386, 392, 394-396, 

398, 401, 422, 428 
— — cinerea, 411; E. scoparia, 491; 

E. tetralix, 425 
Ernodea littoralis, 85, 291, 453 
Ernst, A., on the re-stocking of Krakatau, 

116, 142, 154, 190, 207, 425, 458 
Erodium, 390' 

Erslev, on tropical seeds on the Jutland 
coast, 37, 43 

Eryngium maritimum, 447 

Erythrsea centaur ium, 491 ; E. maritima, 
404; E. massoni, 371, 374, 377, 379, 
387, 402 ; E. ramosissima, 491 

Erythrina, seeds in European drift, 23, 
25-27, 33, 208 {see Buesteen, the 
Norse name) ; E. corallodendron, 209 ; 
E. velutina, 209 

Estuaries; plants, 86, 88, 90, 94 (see 
Mangroves) ; salinity and its influence 
on station, 99-104, 110, 180; under- 
flow of sea- water, 102, 110 

Etna, subterranean and submarine 
streams, 497 

Eucalyptus, the question of its Australian 
origin, 318, 319, 322 

Eucarex, 345 

Eugenia, 318, 454 

Euphorbia azorica, 384, 388, 404, 407, 

421, 428. See E. pinea. 
buxifolia, 86, 279-283, 288, 291, 451, 

452 

canariensis (Cactoid Euphorbia) 

408, 412, 448 
lecheoides, 286 



514 



GENERAL INDEX 



Euphorbia mellifera (Tree- Euphorbia), 
401, 407, 410, 428. See E. stygiana, 
its Azorean form. 

origanoides, 460 

paralias, 448-450 

peplis, 219, 384, 388, 404, 421 

pinea, 384, 388, 404. See E. 

azorica. 

piscatoria, 410 

polygonifolia, 186 

stygiana (Tree- Euphorbia), Azorean 

variety of E. mellifera {see above), 370, 
374, 375, 379, 386, 392, 401, 428 

trinervia, 460 

vaginulata (Burnt-bush), 198, 280, 

281, 283, 285, 288, 289 
Euphrasia grandinora, 375 
Europe : 

Bottle-drift, 46-82 ; from West Indies 
to Europe, 52-55, 59, 65-68, 71, 76, 
79, 80; to the West Indies from 
Europe, 56-59, 66, 68-69, 71, 79, 
80; from the African side of the 
Atlantic to Europe, 59, 76; from 
off the Amazon estuary, 70, 71, 75; 
from Ascension, 76, 482 

West Indian seeds and fruits on 
European beaches, 20-45; baulks 
of mahogany washed ashore, 35, 40, 
42, 48, 78 
Euterpe, 16 

Evans, Lieut., on Sargasso weed in the 
Florida Stream, 485 

Ewart, A. J. ; on seeds of Guilandina 
bonducella and Mango stones washed 
ashore on south coasts of Australia, 
140, 164; on the seeds of Canavalia 
obtusifolia, 190; on Convolvulus sol- 
danella in Australia, 220 

" Extensionists," their views, 272, 273, 
275 

Faba marina, name of Entada scandens,21 

orcadensis, name of Ipomoea tube- 

rosa, 161, 163 

Fagus, 294, 326, 328, 433 

Fairies' Kidneys, a Norse name for the 
stranded seeds of Entada scandens, 23, 
25. See Vette Nyre. 

Falkland Islands, bottle-drift, 63, 74, 78 

Families of plants; grouped into Primi- 
tive and Derivative families, 314-316, 
321; their evolution, 319, 322 

Farewell, Cape, Greenland, bottle-drift 
from the vicinity found on Teneriffe, 
483, 484, 496, and near the North Cape 
of Norway, 495 

Faroe Islands, West Indian seeds 
stranded, 21, 23, 25, 27, 34, 122; 
drift-wood, 40 ; current-connection 
with Iceland, 187 

Fawcett, W., on Jamaican plants, 178, 
185, 193, 194, 197, 198, 200, 253 



Faya, name of Myrica faya, q.v.. 433, 434 

zone, on Pico, 369, 386 

Fayal, origin of name, 433, 434 
Fernando Noronha ; drift seeds, 121 ; 

Acacia farnesiana, 170; Canavalia 

obtusifolia, 191 ; Ipomoea tuba, 220 
Fernow, on Cuban trees, 112, 215 
Ferns. See Acrostichum, Asplenium, 

Dicksonia, Hymenophyllum, Osmunda, 

Pteris, Trichomanes, etc. 
Fevillea cordifolia (Antidote Vine), 3, 7, 

11, 12, 13, 15, 16, 86, 90, 124 
Ficus, 454 

Field Columbian Museum, 9, etc. 

Field en, H. W., on a drift seed in the 

Hebrides, 24, 32, 43, 162 
Fiji, 142, 146, 191 ; Rhizophora, 96-100 
Finmark, West Indian drift seeds, 35, 36 
Fire-shrub, 285 
Firewood, in Azores, 397, 398 
Flores, Azores, junipers, 395, 397 
Florida region : 

Bottle-drift; stranded in this region, 
51, 57, 58, 61, 67, 70-73, 75, 79, 444, 
445, 463, 466; dropped overboard 
in this region, 52, 54, 58, 59, 65, 66, 
71, 75, 467, 468, 471 
Flora, 93, 106, 114, 178, 179, 192, 194, 

210, 220, 225, 252 
Geology, 258, 503 
Sand -keys, plants. See Lansing. 
Seed-drift from the Amazon and 
Orinoco, 7 

Fogh, C, West Indian drift on European 

beaches, 20, 36, 41, 43, 481 
Forbesian hypothesis, extension of 

Europe, 389 
Forster, G. ; plants of Fayal, 361, 385, 

389, 433, 440, 491; plants of Easter 

Island, 156, 246, and of Cape Verde 

Islands, 170 
Foula Island (Shetlands), absence of 

West Indian seed -drift, 34 
Fox, J., West Indian seeds, etc., in the 

Shetland Islands, 34, 40, 162 
France; West Indian seeds stranded, 

26, 28; bottle-drift, 52, 53, 68. See 

Biscay. 
Frankenia, 388, 448-450 
Fredholm, stranded coco -nuts on the 

Lofoten Islands, 37 
Frigate-bird, seed-dispersal, 32, 279 
Fructuoso, on the original woods of the 

Azores, 393 
Fuegia ; Carex and Sphagnum, 337-341, 

352; Uncinia, 498-501; bottle-drift 

and its bearing on dispersal of seed- 
drift, 63, 74, 78, 294-312, 294-296, 

301, 306, 310 
Fulmar Petrel, swallowing West Indian 

drift seeds, 32 
Furnas Valley (Azores), 496 ; trees buried 

in volcanic ashes, 383, 394 



GENERAL INDEX 



515 



Galapagos Islands, their plants, 176, 201, 

227, 236, 400 
Garcinia mangostana (Mangosteen), fruit 

on Scandinavian coast, 28, 36 
Gastridium lendigerum, 491 
Genipa clusiifolia (Seven-year Apple), 87, 

194, 197, 198, 209, 279-283, 287, 291, 

487 

Gentiana centaurium, 491 
Geraniacese, 315, 316 
Geranium, 315; weeds in Azores, 390, 
391 

Glacial period and plant distribution, 

326, 327 
Glaux maritima, 187 
Glossopteris flora, 328 
Gnaphalium luteo-album, 492 
Goats; destructive of young plants in 

the Turks Islands, 139, 231, 232, 277, 

281 ; dispersers of Manchineel seeds, 

115 

Godman, F. du C. ; on the Azorean flora, 
359, 362, 364, 367, 385, 390, 392, 399, 
440 ; on the snow-cap of Pico, 367, 372 

Gomes, B. A., concerning plants from 
the Azores, 364, 434, 440 

Goodeniaceae, as an Australian family, 
227, 228, 314, 317 

Gosse, P. H., on Jamaican pigeons and 
Anona dispersal, 175 

Gourds, in Scandinavian beach-drift, 36, 
146. For general details see under 
Crescentia, 145, etc. 

Grand Canary, strand plants, 448 

Grant, Ogilvie ; on the vegetation of the 
higher slopes of Pico, 367; on the 
Juniper trees of San Jorge, 396; on 
the Azorean pigeons, 418; on missel- 
thrushes in the Azores, 437 

Gray, Asa; Cakile, 184; plant -distribu- 
tion, 327, 329, 330 

Great Lakes of North America, shore 
plants, 186 

Greenland, West Indian seeds and logs 
of mahogany, 35, 40, 42. See Davis 
Strait and Cape Farewell for bottle - 
drift, etc. 

Greenman, Dr., on a new species of 
Morinda, 226 

Grenada; beach plants, 116, 245; 
stranded seed-drift, 6, 13; Grand 
Etang, the lake and its plants, 131, 

Grias, 212, 213 

cauliflora (Anchovy Pear), 3, 6, 7, 

12, 14-17, 86, 90, 106, 124, 147, 205, 
211 

Grisebach, A. H. R. ; on West Indian 
plants, 114, 116, 118, 121, 143-147, 
150, 152, 156, 157, 161, 201, 202, 205, 
210, 211, 218, 225, 227, 250, 251, 285, 
294, 457-459 

Guayas or Guayaquil River. See Ecuador. 



Guernsey, bottle-drift from Ascension, 76, 

81, 482 
Guettarda, 175, 287, 454 
Guianas ; distribution of estuarine drift, 

13, 19, 74; bottle-drift, 61, 73-75; 

Carapa, 141, 142 
Guilandina (genus), 133; seed buoyancy 

and an inland station, 456 
bonduc (Yellow Nicker), 12, 32, 87, 

92, 140, 456 
bonducella (Grey Nicker) : 

Distribution and dispersal by currents, 
87, 92, 138, 139, 291 

General treatment, 138 

Seeds ; in beach drift, West Indian, 5, 
10-12, European, 23-28, 30-36, 
Azorean, 37, 38, and Australian, 140 ; 
drift seeds used, medicinally and as 
charms, 24 ; swallowed by sea-birds, 
32 ; trade in the seeds, 140 ; buoy- 
ancy, 87, 139, 456, 457 

Station, 138, 194, 197, 200, 244, 245, 
287, 288 

melanosperma, 456 

species not identified ; seeds in 

Trinidad beach-drift, 13, 457; plant 

in Jamaican forests, 457 
Guinea Current, 59, 77, 475 
Gulf of; bottle-drift, 67, 71, 74, 76, 

80, 81 ; casks drifted to Norway, 481 
Gulf Nut, name of West Indian seeds on 

European beaches, 22 
Stream ; early reference to it as a 

seed-carrier, 21, 33; ancient course 

across Florida, 93; bearing West 

Indian seeds, 1, 7, 20, 21, 26, 29, 33, 

37, 89 ; the indications of bottle-drift, 

51-55, 58, 65, 66, 68, 71-81, 466-471, 

482^84 

Weed. See Sargasso. 

Gulls, Sea, as seed-dispersers, 421 
Gumprecht, T. E. ; on drift-products of 

the currents in the North Atlantic, 20, 

36, 40, 41, 43, 45, 481 ; old Scandi- 
navian names of stranded West Indian 

seeds, 23, 209 
Gunnerus, J. C, on the tropical seed- 

drift of the Scandinavian coasts, 22, 

35, 36, 41, 43, 146, 153, 173 
Guthnick, the Azorean flora, 359, 362, 

385 

Gygax, a Swiss mineralogist who visited 
the Azores, 362 

Haacke, W., polar origin of faunas, 325 
Habenaria, 375, 377 ; capacity for wind 

dispersal, 424, 425 
Haiti. See Hispaniola. 
Halophytes, 478 ; Turks Islands, 290 
Hammerfest, drifting of casks from the 

Gulf of Guinea, 481 
Hammocks of the Florida vegetation, 93„ 

114, 225 



516 



GENERAL INDEX 



Harrison, Prof., on the lake of the Grand 
Etang in Grenada, 455 

Harshberger, J. W., 331; Ambrosia in 
North America, 173; Anona palustris 
in South Florida, 175-179; Arceutho- 
bium in North America, 426; Wood- 
wardia growing in Sphagnum tussocks, 
378; Bahamas, 192; Bermuda, 206; 
Cuba, 215, 253; Florida, 114, 157, 175- 
179, 194, 210, 225; Jamaica, 17, 168, 
211, 243; Turks Islands, 287; Virgin 
Islands, 116, 244, 457; other West 
Indian islands, 119, 151, 202, 250; 
Lower California, 201, 218, 227; 
Mississippi delta and Louisiana coast, 
191, 218, 252; Texas and Mexico, 167, 
168, 229; southern migration of North 
American plants, 336; the sunken 
Caribbean lands, 152, 213 ; centrifugal 
dispersion from the north, 327; salt- 
marsh and estuarine plants of New 
Jersey, 100, 104, 110 

Hart, J. H. ; Herbarium List of the 
Trinidad flora, 118, 212, 251; Saco- 
glottis amazonica, 7, 134; Entada 
scandens, 118; Fevillea cordifolia, 126; 
Grias cauliflora, 212 ; Ipomoea carnosa, 
218; Thespesia populnea, 244; Vigna 
luteola, 251 

Hartert, E., on the pigeons of the Azores, 
418 

Hartung, G., 363, 385, 440; buried 
Juniper trees, 392, 394 

Hatteras, Cape; bottles thrown over in 
its vicinity, 49, 50, 52, 54, 55, 65, 66, 
78, 467, 468; derelicts from this 
neighbourhood, 50, 72, 472, 473; 
turtle carried past in the Gulf Stream, 
41 

Hawaii; Acacia farnesiana, 167, 169-171 ; 
Ipomcea carnosa, 218; Cassytha fili- 
formis, 191 ; Carex and Sphagnum, 
343, 345; Dracama aurea, 487-489; 
transport of spores only by winds to 
this group, 354, 355; ascending air- 
currents on Mauna Loa, 425; sub- 
marine streams of fresh water, 497; 
Azorean and Hawaiian floras compared, 
399, 400 

Heather, W., old chart of the Azores, 366 
Hebrides; stranded West Indian seeds, 
22-26, 31, 32, 122; derelicts, 50, 68, 
472, bottle-drift, 52, 53, and turtles, 
40^2 

Hedera, dispersed by birds, 417, 418 
canariensis ; in Azores, 369, 376, 

392, 401, 429 ; in Canaries, 406 
Hedley, C, palseographical relations of 

Antarctica, 294, 309, 312, 328, 330, 331 
Hedyotis adscensionis, 460 
Heer, O., 329, 363 

Heilprin, A., aeolian rocks in Bermuda, 
259, 262 



"Hekla," H.M.S., bottle-drift in high 

northern latitudes, 484, 496 
Heliotropium, 449 ; H. curassavicum, 278, 

291, 477 

Hemsley, W. B., 43, 294, 440; West 
Indian beach-drift, 12, 13, 126, 128, 
143; West Indian seeds on European 
beaches, 21, 24, 42, 146, 153, 154, and 
on Azorean shores, 37; dispersal by 
currents, 158, 187, 193, 204, 447, and 
by birds, 198, 252; Arceuthobium, 
426 ; Bermudian flora, 466 ; Ascension 
and St. Helena floras, 459, 460; 
Ipomoea tuberosa, 24, 161, 162 ; Sem- 
pervivum in Canary Islands, 408; 
Mucuna pruriens, 458; Weeds, 391; 
Uncinia, 498-501 ; miscellaneous plants, 
116, 147, 156, 157, 160, 167, 171, 201, 
225, 227, 246, 250, 251, 488 

Henriques, Prof., buried Juniper trees in 
the Azores, 395; Myrica faya in Por- 
tugal, 433, 434; the popular Azorean 
name of Myrsine africana, 434 

Hensen, experiments on currents in Kiel 
Bay, 50 

Henslow, J. S., plants of Keeling Atoll, 
448 

Hepaticse, in Azores, 375, 383 

Hepworth, W. W. Campbell; southern 
pelagic organisms stranded in the 
south of England, 29; Labrador Cur- 
rent, 272; Sabine's casks of palm oil, 
482; Gulf Stream, 43 

Heritiera littoralis, 5 

Hernandia peltata, 454 

Herpes tis monniera, in the West Indies, 
105, 477 

Hibiscus elatus, 16, 214 

tiliaceus, 5, 6, 17, 87, 92, 116, 168, 

170, 172, 178, 214, 245-247 

Hill, A. W., Arceuthobium oxycedri in 
the Azores, 426 

Hillebrand, W., Acacia farnesiana in 
Hawaii, 167-171; other Hawaiian 
plants, 218, 246, 458, 478, 488 

Hillier, J. M., Sacoglottis amazonica, 28, 
134 

Hippocratea, in Trinidad beach-drift, 13 

Hippomane mancinella (Manchineel) ; 
beach-drift, 5, 11-14, 17, 115; dis- 
tribution, 87, 88, 93, 113, 114; dis- 
persal by currents, 87, 88, 93, 95, 113, 
115; station, 93, 114, 194, 244, 245; 
doubtful identity of the tree in the 
Bahamas, including Turks Islands, 286 

Hispaniola (San Domingo and Haiti); 
bottle-drift, 56, 58, 61, 62, 65, 462, 
463, 465, 477; Acacia farnesiana, 167, 
168; old masonry on coast, 491 

Hjalmarsson, J. A., flora of Grand Turk, 
185, 283, 286 

Hoban, M. A., West Indian seeds on 
Irish coast, 31 



GENERAL INDEX 



517 



Hochstetter, C. (father and son) ; on the 
Azorean flora, 359, 362, 363, 365, 370, 
376, 385, 389, 392, 428, 440, 491, 492 ; 
zones of vegetation of Pico, 368, 376 ; 
vertical ranges of plants, 362, 363, 376, 
425, 428-430, 432-438 

Hog-Gum tree. See Symphonia globuli- 
fera. 

Hog-Plum. See Spondias lutea 
Hollies. See Ilex. 

Honduras; bottle-drift, 57, 58, 61, 75. 
See Central America, Nicaragua, and 
Yucatan. 

Hooker, J. D. ; dispersal of plants from 
the north, 324, 327, 329, 330, 354; 
southern floras, 294 ; plant -stocking of 
the Macaronesian islands, 411, 412; 
insular floras, 440; Kerguelen, 500; 
St. Helena, 460; West Indian drift 
seeds on the Azores, 37; Dracaena 
draco, 488; Chrysobalanus icaco, 196; 
Conocarpus erectus, 204; Portulaca 
oleracea, 478; St. Kilda petrels and 
drift seeds, 32 

W. J., Niger flora, 99, 131, 194, 196 

Horn, Cape; bottles and figurehead 
drifting from off the Horn to Australia, 
49, 63, 295, 296, 298; doubling of the 
Horn by bottle-drift and probably 
seed-drift, 63, 74, 78, 81, 300 

Home, J., Fijian plant, 171 

Horse-eye Bean (Mucuna urens), 34, 
458 

Hubbard, Mrs., fruit of Sacoglottis 

amazonica on the coast of Devonshire, 

28, 134, 136 
Humboldt, F. H. A. von; West Indian 

seed-drift in Europe, 20, 41, 43; 

ascending air-currents in the Andes, 

425 ; submarine springs off Cuba, 497 
or Peruvian Current, influence on 

the climate of North Chile and Peru, 

271, 272, 275 
Hunt, Carew ; plants of the Azores, 359, 

363, 385, 427, 435, 440 ; trees buried in 

volcanic ashes, 394 
Hydrocotyle umbellata, in Jamaica, 104, 

105, 107 

vulgaris, in Azores, 360, 371, 377, 

379-381, 387, 402, 417, 429 
Hymengea courbaril (Locust-tree); pods 

in the foreign drift of the Turks Islands, 

11, 140 

Hymenomycetes. See Mushrooms. 
Hymenophyllum tunbridgense, in Azores, 

375, 379, 387 
Hyoscyamus albus, in Azores, 384, 388, 

404, 421 

Hypericum, 410 ; H. foliosum, 369, 392, 
400, 429; H. grandifolium, 400, 407; 
H. humifusum, 492; H. perforatum, 
492 

Hypochceris radicata, 492 



Ianthina shells on English, 29, and 
Azorean beaches, 38 

Iceland ; stranded West Indian seeds and 
mahogany logs, 35, 40, 42; stranded 
bottle-drift, 52, 53, 495; shore-plants, 
187; current-connections, 187 

Iguanas ; in the Turks Islands, 486, 487 ; 
as seed-dispersers, 175, 178, 210, 211, 
291 

Ilex, 406, 408, 417, 418, 429; I. azevinho, 
407 

perado, 369, 370, 373-375, 378, 386, 

387, 392, 398, 400, 406, 407, 429; at 
great altitude in Azores, 373 

Inagua Islands (Bahamas); plants, 168, 
284, 286, 287, 290 ; bottle-drift, 464 

Indian Nuts, old name in Scotland for 
West Indian drift seeds, 23, 24, 31 

Ocean ; its traverse by seed-drift as 

illustrated by bottle-drift, 47, 50, 297, 
298, 301-305, 306-308, 311; passage 
into South Atlantic by bottle-drift, 62, 
63, 74, 80 

Ink-berry. See Scsevola plumieri. 

Insular factor in distribution, 334, 343, 
358 

Ipomoea acetossefolia, 217 

carnosa, 87, 92, 217, 384, 404, 421 

kentrocaulos, 161 

pes-caprse ; general treatment, 219 ; 

seeds in beach-drift, 5, 6, 12, 17, 219, 
242, 446 ; dispersal by currents, 87, 92, 
219, 291 ; distribution of the species, 
87, 217, 218, 219; on the Turks 
Islands, 278-283, 288, and the Florida 
sand-keys, 451, 452, 454; compared 
with Convolvulus soldanella as regards 
range, 220 

tuba, 87, 92, 220, 280, 281, 291, 

292, 452 

tuberosa ; general treatment, 161 ; 

popular name, 210; seeds in West 
Indian beach-drift, 11, 12, 162, and in 
European beach-drift, 24-27, 32-34, 
161-163, being used as charms in the 
Hebrides, 24 

Ireland : 

Stranded West Indian seeds, 26, 30, 
122 

Stranded bottles; one from the 
vicinity of the Cape Verde Islands, 
59, 72, 76; one from the channel 
between the south-eastern Bahamas 
and Hispaniola, 65, 72, 466, 477; 
one from the Caribbean Sea to the 
south of Jamaica, 59, 76; three 
from the seas between Cuba, 
Florida, and the Bahamas, 52; 
seven from the vicinity of Cape 
Hatteras, 49, 52; one from a posi- 
tion to the south-east of Cape Cod, 
50 ; ten from the seas south of Nova 
Scotia and Newfoundland, 52; two 



518 



GENERAL INDEX 



Ireland : Stranded bottles {continued) — 
from Davis Strait, 484, 496 ; twenty- 
three from mid-Atlantic to the 
north-west of the Azores, 52, 53; 
range of the sources of Irish bottle- 
drift from the New World, 55, 79 
A bottle reaching the Bahamas from 
the vicinity of the Irish coast, 57, 
66, 69, 72, 79, 464, 465, 477 
Irminger, C. ; currents, drift-wood, and 
drift-seeds in the North Atlantic, 20, 
35, 40, 41, 43, 45 
Isatis tinctoria (Woad), early cultivation 

in the Azores, 397 
Islands. See Insular factor. 
Islets, Coral-reef; plant -stocking in the 
West Indies and Pacific Ocean com- 
pared, 453, 454 
Isnardia palustris, 104, 105 
Isoetes in the Azores, 380-382, 387, 420, 
429 

Iva imbricata, 451, 453 

Jackson, Capt., on the Guinea Current, 
476 

Jacquin, Von, Rhizophora mangle, 96; 

Hippomane mancinella, 114; Mucuna 

pruriens, 459 
Jacquinia armillaris, 86, 109 
Jamaica : 

Rhizophora mangle, 98-101 

Black River district; infiltration of 
sea-water into the Great Morass, 101 ; 
underflow of sea-water up the 
estuary, 102; springs of the Great 
Morass (Blue Hole), 104; vegetation 
of the river, riverside, and Great 
Morass, 104-106; Great Lake at 
Pondside, 107; Salt Lakes district 
and the vegetation, 107-109, 206 

Savanna -la-mar district ; vegetation, 
106; Cabarita River, 106; Bowen's 
River, 107 

Vegetation, bordering the beaches, 244 ; 
of the woods, 16, 111, 118, 144, 155, 
160, 226, 243; of rivers, ponds, 
mangrove-swamps, 15-17, 104-109; 
of the Blue Hole spring, 104 ; of the 
Roaring River Falls, 16, 147, 211 

Migrating birds on the highlands, 500 

Beach-drift, 3, 6-9, 11, 12, 129; 
seed -drift brought by the Main 
Equatorial Current, 8, 129 

Bottle-drift; brought by the North 
Equatorial Current, 56, 57; by the 
Main Equatorial Current, 61; and 
from the vicinity of Ascension, 474, 
475 

Japan; Sphagnum, 334, 343, 349; Carex, 
349 

Johnson, J. Y. ; the Juniper in Madeira, 
410, 431; plants of the Peak of Tene- 
riffe. 411 



Johnson, T., Arceuthobium, 427 

Jones, F. Wood, 82, 312 ; bottle-drift as 
illustrating plant -dispersal in the Indian 
Ocean, 50, 302, 303, 305, 308 ; snakes 
and crocodiles drifted to Keeling Atoll, 
303, 486; floating corals, 165 

J. M., Sapindus saponaria in Ber- 
muda, 157 

Jonston, J., 43; early allusion to the 
drift fruits of Sacoglottis amazonica, 
137 

Jouan, H. ; on Tahitian and Marquesan 

plants, 171, 247 
Jourdan, S., early reference to Bermudian 

plants, 204 
Juan Fernandez, Uncinia, 498 
Juglandese; fruit in Azorean beach-drift, 

37, 38 

Juglans; fruit in West Indian beach- 
drift, 12, 13 ; distribution of the genus, 
326 

Juncus, 382; capacities for dispersal by 
birds and winds, 418, 419, 422, 424 

acutus, in Azores, 384, 388, 404, 

421, 422 

Juniper, Brown-berried; J. oxycedrus, 
430 

zone in the Macaronesian islands and 

on the Great Atlas, See under J. 
oxycedrus. 

Juniperus bermudiana, 204; J. brevi- 
folia (see J. oxycedrus) ; J. com- 
munis, 401, 430; J. macropoda, 426 ; 
J. nana, 401, 430 

oxycedrus (Cedro, Cedar) ; Azorean 

variety, brevifolia, 430 : 

Affinities of the Azorean tree, 401, 
430-432 

Dwarfing, 373, 374, 382, 383, 387; 
large size in the original forests, 392, 
396; trees buried in volcanic ashes, 
363, 393-395 ; use of the wood, 393, 
397 

Juniper-zone; on Pico, 369, 370, 371, 
373-375, 386, 430; on Teneriffe, 
Madeira, and the Great Atlas, 408- 
410, 415, 416 

Junipers of the Lake District of Pico, 
379, 387; of San Miguel, 382; of 
Terceira, 383 

Source in the Great Atlas, 405, 406; 
dispersal by birds, 417, 418 ; the host 
of Arceuthobium, 370, 375, 379, 386, 
426; fruiting, 373, 430 
Jussisea, 105 

Jutland coast, stranded West Indian 
seeds, 37 

Kamel, Father, mentioned by Petiver, 163 
Keane, A., the lake of the Grand Etang, 
455 

Kearney, T. H., the salt in sea-beaches 
and halophily, 186 



GENERAL INDEX 



519 



Keating, P., buried Juniper trees in 
Flores 395 

Keeling Atoll; plants, 170, 240, 247, 248, 
448; beach-drift, 132, 142, 143; vege- 
table drift, snakes, and crocodiles from 
Malaya, 302, 303, 486; bottle-drift 
indications, 50, 303-305; stranded log 
carrying seeds, 453; floating corals, 
165; frigate-birds and boobies and 
seed-dispersal, 32 

Islands. See above. 

Island, North, 453 

Kellerman, K. F., on denitrifying bac- 
teria, 502 

Kerguelen; bottle-drift and its indica- 
tions, 295-300, 310; a habitat of 
Uncinia, 498-501 

Kermadec Islands, 220 

Kerner, 96, 419 

Kidder, Dr., seed dispersal in the Southern 

Ocean, 500 
Kilkee (Ireland), stranded West Indian 

seeds, 31 
Kleinia neriifolia, 408 
Knowles, Miss M. C, stranded West 

Indian seeds on the Irish coast, 31, 

123 

Knowlton, F. H., Cretaceous and Ter- 
tiary plants of North America, 328 

Knuth, R., Lysimachia, 432; Anagallis, 
480, 481 

Kohl, J. G., on the vegetable drift trans- 
ported in the Gulf Stream to Green- 
land, Faroe Islands, and Europe, 20, 
35, 40, 41, 43, 81 

Krakatau, its re-stocking with plants, 
116, 142, 190, 192, 200, 207, 253, 
458 

Krause, K., on Scsevola, 227-232, 235, 

236, 447, 448 
Kiikenthal, G., on Carex, 334-358; on 

Uncinia, 498-501 

" L'Aigle," \ French sloops in the West 
" L'Emeraud," J Indies in 1753 ; 264, 489 
Labrador Current and climate, 272 
Laccadives, compared with the Bahamas, 

255, 256, 274 
Ladrones, 201 

"Lady Montague" (American ship), 
bottle-drift, 76, 482 

Lagenaria vulgaris, gourds on Scandi- 
navian beaches, 36, 146 

Lagoas, in Pico. See Lakes of Pico. 

Laguncularia, 309 

racemosa; general treatment, 

221; distribution, 86, 221; com- 
parison of the West Indian and 
Ecuadorian plants, 222; vivipary, 4, 
221, 222; fruits in river-drift, 222, and 
in beach-drift, 4, 12, 17, 222, 446; 
plant as a constituent of the mangrove- 
formation, 4, 10, 15, 100, 106, 108, 109, 



202, 203, 283, 289, 454; dispersal by 
currents, 4, 18, 86, 90, 222, 291, 452; 
Florida sand-keys, 182, 451, 452 
Lakes of Pico; Caiado, Das Teixas, Do 
Ilheo, Negra, Paul, Rosada, 379-381, 
437 

Lamium purpureum, 391 

Lansing, O. E., on the vegetation of the 
Florida sand-keys, 9, 115, 139, 156, 173, 
183, 186, 190, 198, 203, 219, 231, 240, 
250, 450 

Lantana involucrata, 285, 288, 292 

La Palma, Canary Islands, 497 

Lapland, stranded seed of Entada 
scandens, 36 

Lathyrus maritimus, 186, 187 

Laughton, J. K., 43; West Indian and 
Mexican seeds and logs of mahogany 
on the shores of Greenland and Ice- 
land, 35, 40 ; Main Equatorial Current, 
70, 443; Counter Equatorial Current, 
476 ; Sargasso Sea, 461 ; waters of 
Amazon estuary, 75 

Laurel-woods of Macaronesian Islands, 
365, 368, 369, 386, 393, 401, 406-410, 
412—416. See Laurus, L. canariensis, 
Persea indica, Oreodaphne fcetens, 
Phoebe barbusana. 

Laurestinus. See Viburnum tinus. 

Laurus, 417 

canariensis (Persea azorica) ; in 

Macaronesia, 401, 413; Pico, 369, 370, 
374, 375, 380, 386, 387, 392, 393, 
432; San Miguel, 382, 432; Teneriffe, 
406, 408; Madeira, 407, 410; size of 
existing trees in the Azores, 392, 395 ; 
used for fuel, 398 

indica. See Persea indica. 

Leathery Turtle, caught off Scilly, 41 

Lecythidacese, 211, 214 

Lefroy, J. H., on Bermudian plants, 139, 
197, 245 

Leguminosse; behaviour of genera hold- 
ing littoral species, 133; Andrews 
on the development of the family, 
318 

Le Maout and Decaisne, Mucuna pruriens, 
458 

Librocedrus, 318, 327 

Lilford, Lord; on the food of Canarian 

wood-pigeons, 418 
Limnanthemum humboldtianum, 223 
Lindman, C, on Scandinavian beach-drift 

from the West Indies, 21, 27, 36, 42, 

43, 122, 123, 146, 153, 162 
Ling. See Calluna vulgaris. 
Linnseus, 22, 37, 173, 448 
Linschoten, J. H. van ; on the forest-trees 

of the Azores in the sixteenth century, 

393, 397, 437, 440 
Liquidambar, 318 
Liriodendron, 318 
Lithophila, 85 



520 



GENERAL INDEX 



Littoral floras, West Indian and West 
African compared, 83-95, 86; tropics 
of the Old and New World compared 
309, 453, 454 

Littoral plants : 

(a) Genera holding both littoral and 
inland species; Anona, 175; Bar- 
ringtonia, 175; Calophyllum, 156, 
175; Canavalia, 133; Chryso- 
balanus, 196; Clerodendron, 175; 
Coccoloba, 197; Colubrina, 200; 
Cordia, 175; Erythrina, 208; 
Guettarda, 175; Guilandina, 133, 
456; Hibiscus, 214; Luff a, 223; 
Morinda, 175, 226; Portulaca, 
478; Scgevola, 175, 230; Sophora, 
133, 237-239; Terminalia, 116, 
175, 231; Tournefortia, 248. For 
a discussion of the subject, see 
chapters xiv, xv, xvi, of my book 
on Plant-Dispersal, a list of genera 
being given on p. 134. 

(b) The relation between a littoral 

station, buoyancy of seeds and 
fruits, and dispersal by currents, 
139, 140, 169, 216, 223, 229, 238, 
239, 456, 457 

(c) The relation between a littoral 

station and xerophily, 169, 175, 
216, 229, 239, 288, 293. See 
pp. 32, 39, 201, 515, of Plant- 
Dispersal. 

(d) The extension of inland plants to 
the coast, 229, 288, 293, 448 (see 
p. 131 of Plant-Dispersal); and 
the extension of littoral plants 
inland, 219, 227, 237-239, 288, 
293. See under Littoral plants 
in index of Plant -Dispersal for 
further data. 

(e) Littoral plants as parents of inland 

species, 226, 456, 478. See Plant- 
Dispersal, pp. 133-170. 
(/) Littoral plants of the same genus 
dividing the tropical world between 
them, 227, 228; Carapa, 141, 228; 
Rhizophora, 141, 228; Scsevola, 
227, 247 ; Tournefortia, 228, 247 < 

(g) Littoral plants where both frugi- 

vorous birds and marine currents 
disperse the species; Cassytha, 
192; Scsevola, 230, 232; Ximenia, 
252 

(h) Littoral plants of the Azores, 384, 

404 ; Jamaica, 106, 244 ; Teneriffe, 
448; Turks Islands, 290, 291; 
West Indies, 86, 87 
Littorella lacustris in the Azores, 371, 

378, 380, 381, 387, 403, 417, 420, 429, 

432 

Lloyd-Jones, A., Entada scandens seed 

in Swansea Bay, 30 
Locust-tree. See Hymensea courbaril. 



Logs, drifting; transporting seeds, 248. 

291, 418, 421 
Lomba, an eminence on the upper slope 

of Pico, 360 
Loranths. See Arceuthobium and Phora- 

dendron. 

Lord Howe Island, possessing New 

Zealand Carices, 348 
Loro (Louro), Laurus canariensis, 432 
Losningsteen, Norse name of Entada 

scandens, 23 
Lottin, seed of Entada scandens found 

near the North Cape, 36 
Lotus, 390; L. angustissimus, 492 
Louisiana; stranded bottle-drift, 58; 

shore plants, 191, 218 
Lowe, R. T. ; Madeiran flora, 185, 406, 

407, 410, 411, 435-437, 440; the 

Salvages, 449 
Lowenorn, Von; drift-wood in high 

northern latitudes, 35, 40, 45 
Lucuma, 29; L. mammosa, 29 
Luffa, 223 

Lumnitzera, 309, 454 

Luzula, means of dispersal, 419, 427 

purpureo-splendens, 371, 377, 387, 

402 

Lycoperdon (Puff-ball), falling rate of 

spores, 424 
Lycopodium ; falling rate of spores, 424 ; 

L. selago, 371, 374, 377, 379; L. com- 

planatum, 375, 380; L. plumosum, 

492 

Lyngbye, H. C, West Indian seeds and 
drift-wood in the Faroe Islands, 35, 40, 
43, 122 

Lysimachia nemorum, var. azorica, 371, 
374, 377, 379, 387, 402, 419, 422, 432 

Macaronesian Islands (Azores, Canaries, 
Madeira); floras compared, 365, 385, 
396, 398-416; plants of the woods, 
406, 407, 415; zones of vegetation, 
407-411, 415, 416; summit vegetation, 
411, 416; history of their plant-stock- 
ing, 411-414, 416; American elements, 
412; comparison of climate and con- 
ditions, 365, 409 ; the dispersing agency 
and subsequent differentiation of the 
pigeons, 418; the Campanulas, 428; 
Juniperus oxycedrus, 431, 432 

Machado, C, Portuguese botanist, 359, 
364, 385 

McKeehan, L. A., falling rates of spores, 
423 

Madagascar; bottle and seed -drift and 
their tracks, 301, 304, 305; Sphag- 
num and Carex, 334, 343-346 

Madeira : 

Bottle-drift; recovered on the island, 
52, 53, 54, 484, 485; dropped into 
the sea in the vicinity, 56, 57, 67, 
464, 465 



GENERAL INDEX 



521 



Madeira (continued) — 

Flora compared with those of the 
Azores and the Canaries (Teneriffe), 
365, 385, 398-416, 406-411. See 
under Macaronesian Islands for the 
details of the comparison. 
West Indian seed -drift, 38 
Magdalena River, 17 
Mahogany logs, transported by currents 
to Greenland, Iceland, and North- 
West Europe, 35, 40, 42, 48, 78 

canoe made of ; stranded on the 

Faroe Islands, 40 
Maiden, J. H., on the overlapping of the 
ranges of Ipomoea pes-caprse and Con- 
volvulus soldanella in eastern Australia, 
220 

Maize, half-eaten cobs in beach-drift of 

South Devon, 29 
Malagasy province, Sphagnum and Carex, 

334, 343-346 
Maldives, compared with the Bahamas, 

255, 256, 274 
Malva; M. mauritiana, 492; M. nicseen- 

sis, 492 
Mamillaria, 224, 287 

Mammea, 84, 144, 326; M. americana, 

4, 11-13, 87, 91, 144 
Manchineel. See Hippomane mancinella. 
Mangifera indica (Mango); "stones" in 

beach-drift, 11, 30, 164 
Mangle grande and Mangle chico (Rhizo- 

phora mangle), 99 
Mangosteen (Garcinia mangostana), in 

European beach-drift, 28, 36 
Mangroves : 

Dispersal by currents, 86, 90, 94, 96, 
451, 452 

Mangrove-formation; West Indies, 4, 
18 ; Turks Islands, 10, 289 ; Jamaica, 
15, 106, 108-110; Florida sand-keys, 
450 ; West Indian and West African 
compared, 86, 89, 90; Asiatic and 
and American compared, 309, 454 

Mangrove fruits and seedlings in beach- 
drift, 4, 10, 12, 15, 17, 18, 446, 451, 
452 

Stocking of islets with mangroves, 451 
Vivipary of mangroves, 4, 502 
(Further details will be found under 

Avicennia, Rhizophora, and Lagun- 

cularia) 

Manicaria saccifera, 3-8, 11-14, 17, 25, 

26, 31, 75, 86, 90, 127 
Mann, H., Hawaiian flora, 170 
Marantacese, 315 
Marianne Islands, 201 
Marias Islands, 201 

Martin, M., on the West Indian seed-drift 
of the Hebrides and Mull, 22-25, 31, 
41, 43 

Martins, Ch. ; effects of sea-water immer- 
sion on seeds, 188, 447 ; a pod of Cassia 



fistula washed up in the south of 

France, 154 
Martius, on Manicaria saccifera, 128 
Martyr, Cassia fistula in the West Indies, 

155 

Mary's Bean or Virgin Mary's Nut, names 

of stranded West Indian seeds in the 

Hebrides, 24 
Mascarene Islands, Sphagnum and Carex, 

334, 343-346 
Masson, F., Azorean plants, 361, 385, 440, 

493 

Masters, on buried Juniper trunks from 

the Azores, 395 
Matricaria maritima, 187 
Mauritius, Carex and Sphagnum, 344-346 
Mayor, F. S., earliest cultivated plants 

in the Azores, 397, 440 
Medanos, moving sand-dunes in Peru, 

270, 271, 493-495, 503, 504 
Medicago, 390 

Mediterranean, bottle-drift from the 

Atlantic, 53, 56 
Melocactus communis (Turk's-head Cac- 
tus), 202, 224, 280, 283, 287, 292 
Mentha; M. pulegium, 492; M. rotundi- 

folia, 492 
Menzies, Conocarpus erectus, 201 
Menziesia, distribution, 419 
polifolia (St. Dabeoc's Heath), 370- 

373, 377, 386, 387, 402, 411, 433; 

means of dispersal, 417, 419, 422 
Mertensia maritima, 187 
Mesembryanthemum ; a doubtful species 

in the Azores, 384, 404 ; M. crystallinum 

and M. nodiflorum in the Canaries and 

Salvages, 448, 449 
Mesquite (Prosopis juliflora), 168 
Mexico, Gulf of; bottle-drift and its 

indications, 57, 58, 61, 67, 71-73, 79, 

444, 445 

Miers, J., on Crescentia cucurbitina, 149; 
on Grias cauliflora, 211 

Milium lendigerum, 491 

Millspaugh, C. F. ; author's indebtedness, 
9; Cakile, 184-189 ; Conocarpus erectus, 
201, 203; Ipomoea carnosa, 217-219; 
Alacran Shoals, 187, 188, 201, 231, 
240, 250; Cayman Islands, 138, 192, 
197, 201, 206, 221, 225, 240, 250, 251, 
456; Florida sand-keys, 115, 156, 182, 
183, 203, 204, 231, 232, 450-453; 
Turks Islands, 278-287, 291; Porto 
Rico, 99, 168, 192 ; Jamaica and Cuba, 
168, 251 ; Bahamas, 114, 210, 220, 225; 
Yucatan, 157, 227 

Milner, Sir W., West Indian drift seeds 
in the crops of petrels at St. Kilda, 
31, 32 

Mimosa scandens, 32, 35 

Missel-thrush, as a disperses of Juniper 

seeds, 437 
Mississippi delta, vegetation, 218, 252 



522 



GENERAL INDEX 



Molesworth, Lord; marginal notes in 
Martin's book on the Hebrides, 43 

Molucca Beans, old name in Scotland 
and the islands for West Indian drift 
seeds, 22-25, 31-33, 42, 163, 458 

Monaco, Prince of, investigations with 
floats in the North Atlantic, 43, 47, 
49, 51, 52, 53-56, 64, 68, 79-81, 461, 
466, 469, 472, 483, 484 

Monarde, N., old Spanish botanist, 45 

Montevideo, bottle-drift, 71 

Montrichardia arborescens, 455 

Morelet, A., on the Azorean flora, 363, 
365, 368-370, 374, 385, 440 

Morinda, 175, 226; M. royoc, 87, 88, 93, 
95, 225 

Morocco, stranded bottle-drift, 51, 52, 53 

Moronobea coccinea, synonym in part for 
Symphonia globulifera, q.v. 

Morris, Sir D. ; Jamaican beach seed- 
drift, 7, 11, 12, 75, 112, 118, 128, 152, 
190, 458; Sacoglottis amazonica, 28, 
43, 133-137 ; dispersal of Uncinia, 337, 
500 ; Orinoco and Amazon drift, 7, 75 

Moseley, Miss M., a seed of Entada 
scandens near Boulogne, 28 

Prof. ; seed-drift off the coast of 

New Guinea, 132, 155, 190; Fernando 
Noronha, 170, 191, 220; dispersal in 
the Southern Ocean, 500 

Mouchoir Shoal, 255, 258, 264 

Mountains, ascending air-currents, 355, 
425, 439 

Mucuna; problems of the distribution of 
the genus, 133; unidentified species in 
the Trinidad beach-drift, 13, 121, 124 

altissima, 120-123, 455, 459 

pruriens, 122, 457-459 

urens ; general discussion, 120 ; 

station, 16, 87, 91, 123 ; seeds in West 
Indian beach-drift, 11-14, 17, 121, 
131 ; seeds in European beach-drift, 4, 
22, 25-28, 26, 31-36, 122, 123, 131; 
seeds in Azorean beach-drift, 37, 38; 
dispersal by currents, 87, 123; species 
confused with M. pruriens, 122, 457- 
459 

near M. urens, 87, 120 ; seeds in 

West Indian beach-drift, 11-13, 121, 
131 ; seeds in European beach-drift, 
26-28, 34, 122, 123, 131, and in 
Azorean beach-drift, 37, 38 

Mueller, Baron F. von; on Acacia farne- 
siana, 166, 172; on Juniperus com- 
munis, 431 

Miiller, K., currents and plant-dispersal 
in the southern hemisphere, 39, 43 

Mull, stranded West Indian seeds, 24, 31 

Murray, Sir J., quoted by Wallace, 422 

Musacese, 315 

Mushrooms, falling rates of spores and 
dispersal by winds, 355, 423, 424, 439 
Mutisiacese, 327 



Myrica faya; in Azores, 369, 375, 376, 
382, 386, 392-395, 398, 401, 433, 435; 
in Canaries, 406, 408; in Madeira, 406, 
407, 410; means of dispersal, 417, 418; 
long established in Portugal, 361, 433, 
434; origin of the name, Faya, 433 

Myrsinacese, 314, 315 

Myrsine africana, 369, 370, 374-376, 380, 
382, 383, 386, 392, 401, 406, 413, 
434 

Myrtacese, Andrews on the development 

of the order, 317 
Myrtus communis, 392 

Nash, G. V., plants in the Inaguas and 

in the Turks Islands, 286, 287 
Natal, bottle-drift from off the coast to 

Brazil, 62, 63 
Natural Order. See Family. 
Nautical Magazine, bottle-drift data, 46, 

50, 54, 57, 66, 69, 443, 464, 474, 482- 

484, etc. 
Navidad Shoal, 255, 258, 264 
Neill, P., Molucca beans, 43 
Nepenthacese, 315 
Nerium oleander, 491, 492 
Nertera, 294 

Neumayer, G., bottle-drift in high 
southern latitudes, 49, 81 

"Newcastle," H.M.S., bottle-drift in 
North Atlantic, 50 

Newfoundland, bottles thrown overboard 
south of this region, 52, 53, 55, 66, 68 

" New York," s.s., bottle-drift, 49, 465 

New Zealand; Sphagnum and Carex, 
332-358, 347-352, 357 ; Uncinia, 498- 
501 ; bottle-drift and current-connec- 
tions, 294-312, 299, 309-312 

Nicaragua, bottle-drift, 50, 57-59, 61, 
475 

Nicker (Nickar), West Indian name of 
Guilandina seeds, 30, 34, 140, 457 

Niger ; probability of its seed-drift reach- 
ing not only Brazil and the West Indies 
but also Europe, 74, 81 ; flora, 99, 131, 
159, 194, 196, 207 

Niihau (Hawaiian Islands), Ipomcea 
carnosa, 218 

Nipa fruticans, 128, 168 

Norfolk Island, possessing New Zealand 
Carices, 348; current-connections, 297, 
298 

North Cape (Norway) ; West Indian seeds 
stranded on and doubling the cape, 36, 
78, 81 ; stranded bottle-drift, 54, 55, 65, 
495 

Norway; stranded West Indian seeds, 
21-23, 27, 35, 36, 78, 81, 173; stranded 
bottle-drift, 52, 53, 65, 495; Cakile in 
beach-drift, 186, 188; casks from the 
Gulf of Guinea, 76, 81, 481 ; mahogany 
baulks from the West Indies, 40 

Notelsea excelsa. See Picconia excelsa. 



GENERAL INDEX 



523 



Nova Scotia, bottles thrown overboard 

south of this locality, 52, 66 
Nymphsea ampla; in Jamaica, 16, 105, 

107 ; in Grenada, 455 

Ocean-holes, in the Bahamas, 258, 276, 
503 

Ochrosia, 5, 454 

O'Connell, S., West Indian seeds on Irish 
coast, 31 

O'Dowd, Miss, seeds of Guilandina bondu- 
cella on the shores of South Australia, 
140 

Olafsen, drift-wood in high northern lati- 
tudes, 45 
Oleander, 491, 492 

"Olive" tree (Bucida buceras), 16, 17 

Oliver, D., 134, 150, 251 

Omphalea; O. diandra, 11-13, 159, 227; 

O. triandra, 160, 226 
Oolitic structure, in the seolian sandstone 

of the Bahamas, 260-262, 502-504 
Opuntias, 168, 204, 224, 278-280, 282, 287 
Orchids; falling rate of seeds and their 

dispersal by winds, 354, 355, 422-425, 

439. See Habenaria and Serapias. 
Oreodaphne f oetens, 408 
Orinoco seed-drift and its distribution 

over the West Indian region, 6, 7, 8, 

13, 19, 74, 75, 81, 129, 141, 486 
Orkney Islands; stranded West Indian 

seeds, 22, 25, 26, 32, 122, 162, 163, 

458; stranded bottle-drift, 52, 53, 471 ; 

stranded turtle, 40 
Ormesteen (Adder -stone), old Norse name 

of the drift seed of Guilandina bondu- 

cella, 23 
Ornithopus perpusillus, 492 
Orton, Dr., pelagic organisms on English 

beaches, 29 
Osborn, J. F., map of Grand Turk, 268, 

491 

Osmunda regalis, in Azores, 369, 376, 
380, 434 

Ostboe, Sargasso weed in the vicinity of 

the Azores, 485 
Ostenfeld, West Indian seeds on the 

Faroe Islands, 35, 44 
Owen, Captain; survey of the Turks 

Islands, 489, 490 
Oxalidaceae, 315 

Oxalis corniculata, in the Azores, 390, 
391 

Pacific Ocean : 

Beach-drift of the tropical Pacific and 
of the West Indies compared, 5 

Bottle-drift, seed-drift, and the cur- 
rents; number of bottles, 47; con- 
nection round the Horn with the 
South Atlantic, 63, 74, 300; across 
the South Pacific from New Zealand 
and Antarctic Islands, 295, 299, 300, 



Pacific Ocean (continued) — 

306-310; across the tropical Pacific 
from equatorial America, 297, 298, 
306, 310 

Vegetation of coral-reef islets in the 
West Indies and in the Pacific 
Ocean compared, 453, 454 
Page, J. ; bottle-drift observations of the 

U.S.A. Hydrographic Office, 81, 312; 

a remarkable drift from off Cape Horn 

to Queensland, 295, 296 ; an interesting 

drift in the tropical Pacific, 297 
Paki, Jamaican name of Crescentia cucur- 

bitina, q. v. 
Palma (Canaries), Juniperus oxycedrus, 

408 

Panama Isthmus ; plants, 132, 191 ; 

beach-drift, 6, 14, 17 ; derelict stranded 

from Cape Hatteras, 72 
Pancratium, 194, 447 
Pandanaceas, 315; Pandanus, 5, 454 
Pantropical genera, 319 
Pao branco, Azorean name of Picconia 

excelsa, q. v. 
Paritium, synonym in part for Hibiscus. 

See under H. elatus, H. tiliaceus. 
Parlatore, Prof., on Juniperus brevifolia, 

431 

Parrots, in connection with the dispersal 

of Anona seeds, 175 
Parry, Captain, bottle-drift in high 

northern latitudes, 484, 496 
Passiflora; fruits in beach-drift in South 

Devon, 30, 289; P. pectinata, 289; 

P. cuprea, 289 ; modes of dispersal, 289 
Pauw, De, on drift-wood in high northern 

latitudes, 45 
Pavonia corymbosa, 105 
Pax, F., Hippocratea, 13; Hippomane 

mancinella, 113-115; Hymensea, 140; 

Omphalea, 160, 227 ; Lysimachia ne- 

morum, 432 ; Anagallis filiformis, 480, 

481 

Pea-nut. See Arachis hypogoea. 

Peel, C. V., on West Indian seeds and 
turtles thrown up on the Outer Heb- 
rides, 32, 40, 44, 122 

Peirce, G. J., dispersal of Arceuthobium, 
427 

Pelagic organisms of warm latitudes on 

English beaches, 29 
Pennant, T. ; West Indian seeds and other 

drift stranded on the Hebrides, 22, 24, 

32, 40, 41, 44, 161, 163 
Penzig, O., the new Krakatau flora, 116, 

142, 154, 190 
Peplis portula, in the Azores, 371, 378, 

380, 387, 403, 417, 420 
Persea, 318 

azorica. See Laurus canadensis. 

indica (Laurus indica), 369, 386, 

401, 406-^08, 435; dispersed by 

pigeons, 418 



524 



GENERAL INDEX 



Peru; medanos or moving sand-dunes, 
270, 271, 493 

Peruvian (Humboldt) Current, its in- 
fluence on climate, 271, 272, 275 

Peterson, P., respecting Foula in the 
Shetlands, 34 

Petherick, on drift-wood in high northern 
latitudes, 45 

Petiver, J. ; West Indian seeds on Euro- 
pean beaches, 41, 44 ; Ipomoea tuberosa, 
33, 161, 163; Manicaria saccifera, 128; 
Sacoglottis amazonica, 137 

Petrels ; West Indian drift seeds in their 
crops, 31, 32; as seed-dispersers in the 
Southern Ocean, 500 

Philodendron, 16 

Phoebe, 412 ; P. barbusana, 408 

Phoenix canariensis, 408 

Phoradendron, 194 

Phragmites, 179, 252, 377 

Phyllanthus, 168 ; P. epiphyllanthus, 280, 
281, 283, 285, 288, 292; P. falcatus, 85, 
210 

Physalia (Portuguese man-of-war), in 
beach-drift; south of England, 29; 
Azores and Canaries, 38 

Physalis peruviana, 491 

Phytelephas macrocarpa (Vegetable 
Ivory), 17 

Piazza, Captain; bottle-drift on east 

coast of Africa, 303 
Picconia excelsa (Notelsea excelsa), 369, 

376, 386, 392, 401, 407, 408, 410, 418, 

435 

Pico (island and mountain of). See 

under Azores. 
da Vara, San Miguel, 382, 383, 430- 

432 

Topo, corrected altitude of, 365, 379 

Pigeons, as seed-dispersers. See under 
Birds. 

Pigs, agents in dispersing seeds, 112, 144, 
175, 243 

Pines, in the Macaronesian islands, 408- 
410 

Pinus canariensis, 408, 409 

" Pique," H.M.S., bottle-drift from Ascen- 
sion, 482 

Piscidia erythrina, 208, 209 

Pistias, 3, 16, 104, 105, 107 

Pithecolobium ; represented in Turks 
Islands, 287, 292; P. filicifolium, 111 

Plantago; mode of dispersal, 418, 421; 
PI. coronopus, 384, 404, 421; PI. 
lanceolata, 390 ; PI major, 390 

Plate River (La Plata), estuary of, con- 
cerning the distribution of its seed- 
drift, 62, 73, 74, 81 

Plocama pendula, 408, 448 

Pluchea, 285, 292 

Plukenet, on Manicaria saccifera, 31, 128, 
129 

Podocarpus, 294, 327 



Polycarpon tetraphyllum, 491 

Polygala vulgaris, on Pico, 370, 371, 372, 

374, 377, 379, 386, 387, 402, 417, 435 
Polygonum; dispersal by birds, 418, 421 ; 

P. glabrum, 105-107; P. maritimum, 

219, 384, 388, 404, 421 
Polymorphous species, 313, 314, 322 
Polytrichum, growths of, in the Azores, 

371, 377, 379, 382, 383, 387; falling 

rate of spores and their dispersal by 

winds, 424 
Pontederia (Water Hyacinth), 3, 16, 105, 

107 

Pontoppidan, E., on the West Indian 
seeds of Scandinavian beaches, 21, 35, 
41, 44 

Populus (Poplar), Portuguese names, 434 
Porto Pym (Azores), beach plants, 218, 
219, 384 

Rico, stranded bottle-drift, 56, 58, 

62 

Portsmouth (England), West Indian seed 
stranded, 28 

Portugal; stranded bottle-drift, 52, 53, 
68; bottles cast into the sea off the 
coast, 57, 66 

Portuguese Current, 54, 56 

Portulaca ; P. halimoides, 109 ; P. oleracea 
277, 279-281, 291, 477, 478; peculiar 
species in islands, 478 

Potamogeton ; fruits in floating river and 
pond-drift, 16, 420; dispersal by water- 
fowl, 417, 420; P. fluitans, 107; P. 
natans, 378; P. plantagineus, 104, 105, 
107; P. polygonifolius, 371, 378, 380- 
382, 387, 403, 420 

Potentilla tormentilla, 371, 377, 379, 387, 
402, 417, 419 

Pouchet, F. A., currents in the southern 
hemisphere, 39, 44 

Povelsen, on drift-wood in high northern 
latitudes, 45 

Praeger, R. Lloyd ; West Indian seeds on 
the Irish coasts, 31; falling rates of 
seeds in connection with dispersal by 
winds, 354, 422-425, 439; seed- 
buoyancy, 447, 473 

Praia, Sir D., on the wood of buried 
Juniper trees in the Azores, 395 

Premna, type of buoyancy in " stones " 
of drupaceous fruits, 234 

Prickles in beach-drift, 164 

Prickly Pear. See Opuntia. 

Prickly- Yellow (Zanthoxylum), prickles 
in beach-drift, 164 

Primocarex, 345, 357, 501 

Primulacese, 314, 315 

" Prince Eugene," s.s., bottle-drift from 
off the Amazon to Florida, 75, 445 

Prioria copaifera, fruits in beach-drift, 
6, 17 

Problem plants. See Acacia farnesiana, 
Campanula vidalii, Chrysobalanus icaco, 



GENERAL INDEX 



525 



Colubrina asiatica, Crudya spicata, 
Grias cauliflora, Hibiscus tiliaceus, 
Hippo mane mancinella, Myrsine afri- 
cana, Symphonia globulifera, Thespesia 
populnea 

Prosopis, 102, 168 

Proteaceae, 317, 327 

Primus lusitanica, 392, 400 

Psamma arenaria, 186 

Pteris aquilina (Bracken), 371, 375-377, 
379, 387, 492 

Puff-ball (Lycoperdon), 424 

Pumice, in the interior of San Miguel, 
382, 383, 479; in beach-drift, 6, 164, 
242, 248, 446, 479; as seed-carriers 
across seas, 248, 291. 

Purdy, J., in " Columbian Navigator," 
81; bottle-drift, 64, 465; boa-con- 
strictor transported across the sea, 486 

Pusey, J. H. ; Turk's-head Cactus, 224 ; 
Grand Turk, 285 ; bottle-drift in Turks 
Islands, 462. 

Quercus, 326 

Race, Cape; bottle-drift. See under 

Newfoundland. 
Randia aculeata, 287 
Ravenala, 326 

Rein, Dr., on the Calabash-tree in Ber- 
muda, 146 
Reinecke, F., Samoan flora, 171, 246 
Remy, Niihau, Hawaii, 218 
Rendle, Dr. : 

Conocarpus erectus and its alleged 
occurrence in the Pacific islands, 201 
Foreign seeds in European beach-drift ; 
Xpomoea tuberosa, 162; Lucuma, 
species, 29 
On Jamaican plants, 178, 184, 185, 

193, 194, 197, 198, 200, 253 
The use of the name, Mucuna pru- 
riens, 459 

Rennell, J.; currents of the North 
Atlantic, 20, 82; bottle-drift of high 
northern latitudes, 46, 50, 57, 66, 484, 
496; drift of a bottle from Ascension 
to Guernsey, 482 ; Sargasso weed, 485 ; 
drift-wood, 45 

Reseda luteola, 491 

Retama(Spartocytisus nubigenus),409,41 1 

Rhachicallis rupestris, 85, 279, 291 (Rh. 
maritima is a synonym) 

Rhamnus, 406, 408, 417, 418 ; Rh. glandu- 
losa, 410; Rh. latif olius, 369, 375,386, 
400, 407, 436; Rh. lycioides, 434 

Rhinoceros, seed of Entada scandens 
found in its caecum, 120 

Rhizophora ; distribution, 141, 228, 309 ; 
period required for the growth of seed- 
lings on the tree, 96, 109 ; Rh. conju- 
gata, 96; Rh. mucronata, 96, 99, 100, 
141 ; Rh. racemosa, 99 



Rhizophora mangle : 

Distribution, 86, 141, 228, 308; dis- 
persal by currents, 4, 86, 90, 291; 
seedlings in beach-drift, 4, 12, 17, 
446 

Period required for the growth of the 
seedling on the tree, 96 ; on its ability 
to withstand drying, 96; on the 
proportion of germinating fruits with 
more than one seedling, 98; the 
absence of dimorphism in the West 
Indies, 99, 110; the length attained 
by the seedlings on the tree, 99 ; the 
influence of varying degrees of salinity 
on the station, 99; colonies in the 
midst of the Black River Morass, 102. 
In Jamaica, 15, 106, 108-110; Turks 
Islands, 10, 283, 289; Ecuador, 178; 
Florida sand-keys, 451-454 

Ribiera Grande bluffs, Pico, 366, 496 

Rice, Prof., Bermudian seolian rocks, 259 

Ricinus communis, 290, 447 

Ridley, H. N., plants of Fernando No- 
ronha, 121, 170, 191, 220; Cassytha 
filiformis in the Malay Peninsula, 192 

Rio de la Plata. See Plate River. 

Negro, 131 

Rivers ; as sources of seed-drift, 2, 3, 18, 
etc. ; germination of floating fruits and 
seeds in river-drift, 3, 5, 15, 16, 18, 
125, 127, 205, 213, 243; temperature 
of head-springs, 104. See Black River 
under Jamaica, Guayas River under 
Ecuador, Amazon, Orinoco, etc., and 
Estuaries. 

Robert, E., on the stranding of seeds of 
Entada scandens near the North Cape 
and in the White Sea, 36, 44; drift- 
wood in high northern latitudes, 45 

Rodriguez Island, Sphagnum plants, 344, 
346 

Romano, or Romani, Azorean name of 
Vaccinium cylindraceum, 437 

Ross, Captain; bottle-drift in Davis 
Strait, 484, 496 

Rubus species in Azores, 369, 376, 400. 

Ruderal plants. See Weeds. 

Rumex, 390 

Russell, H. C. ; bottle-drift in Australian 
waters, 295, 299, 312 

Sabal; S. umbraculifera in Jamaica, 16, 
105, 106, 109; S. palmetto of South 
Florida, 179 ; S. blackburniana of Ber- 
muda, 204 

Sabine, Sir E., on the drifting of casks 
from the Gulf of Guinea to the north 
of Norway, 76, 81, 481, 482 

Lady, 497 

Sable Island and Cape Sable. See under 

Nova Scotia. 
Sacoglottis amazonica, 3-7, 11-14, 17, 

25-28, 31, 86-88, 90, 91, 93, 95, 133, 



526 



GENERAL INDEX 



For its representation in European 
beach-drift, see pages 26, 133-137. 
Safflower, 492 

Safford, W. E., on the genus Anona, 174- 
181 

Sagina procumbens, the possibility of its 

dispersal by winds, 422, 424, 439 
Sagittaria; S. lancifolia of Jamaica, 16, 

104-107, and of South Florida, 179 
Sagot, M. P., on Mucuna pruriens, 459 
St. Croix, 6 ; shore plants, 244, 456, 457 
St. Dabeoc's Heath. See Menziesia 
polifolia. 

St. Helena ; position with reference to the 
equatorial currents and the indications 
of bottle-drift, 60, 443, 474, 475, 531; 
the flora and the currents, 459, 460 ; en- 
demic species of Carex and Sphagnum, 
343 

St. Kilda, 31, 32 

St. Michael's, Azores (San Miguel), 382, 

387, 393, 396, 397 
St. Paul, Southern Ocean, Uncinia, 498, 

501 

St. Paul's Rocks, Equatorial Atlantic, 
bottle-drift from their vicinity, 50, 59, 
61, 67, 70, 443, 444, 475 

Salcombe, South Devon, stranded West 
Indian seeds with other seed-drift and 
pelagic organisms, 28, 29, 30 

Salicornia ; in Jamaica and Ecuador, 101, 
106, 108, 109; S. ambigua in Turks 
Islands, 283, 290-292, and in the 
Florida sand-keys, 451-453; distribu- 
tion and mode of dispersal of the genus, 
452, 453, 478 

Salinity of estuaries. See Estuaries. 

Salix, 179 

Salsola kali; in the Azores, 219, 384, 388, 
404, 421 ; fitness for dispersal by cur- 
rents and birds, 421, 447 

Salt Key Bank, L. Agassiz on the, 261 

Lakes district. See under Jamaica. 

Salt-rakers, in the Turks Islands, 277, 487 

Salvages, Mesembryanthemum, 449 

Samolus valerandi, Azores, 421 

Sampaiao, J. A. N., Portuguese botanist 
in the Azores, 359, 364, 385 

Sand-dunes, 503. See under Medanos. 

San Domingo. See Hispaniola. 

Sand-keys ; Florida, vegetation and plant 
stocking, 450-453, comparison of vege- 
tation of sand -islets in West Indies and 
tropical Pacific, 453 

Sanguinho, Azorean name of Rhamnus 
latifolius, 436 

Sanicula azorica, 375, 418 

San Jorge (Azores), 364, 397, 427^29, 
432-438 ; Juniper trees, 396 

Miguel (Azores); flora, 382, 387; 

original forests and their destruction, 
393, 396, 397; buried Juniper trees, 
393-395 



Santa Barbara, Terceira; vegetation, 
383, 387 

Maria, West Indian name of Calo- 

phyllum calaba, q.v. 

Rosa River, Ecuador, 100 

Sapindus saponaria, 11, 25, 26, 37, 87, 

88, 91, 95, 156, 219 
Sapium, 114 

Sapotacea ; seeds stranded on the Devon- 
shire coast, 29; represented in the 
floras of Madeira, Cape Verde Islands, 
and Hawaii, 410, 488, 489 

Sargasso Sea, 38, 64, 461, 485 

Weed; in the Gulf of Mexico 

and the Florida Stream, 485; in the 
beach-drift of the West Indies, 6, of the 
Turks Islands, 446, of the Azores, 38, 
485, of Cornwall and Shetlands, 486 

Sarraceniacese, 314, 315 

Sassafras, 318 

Saussure, Necker de, 44; stranded West 
Indian seeds and turtles in the Hebrides, 
32, 40, 41 

Savanna-la-mar, Jamaica, vegetation, 
106 

Scsevola, 171, 175, 192, 193, 207, 227, 
447; Sc. kcenigii, 227, 447, 454; Sc. 
lobelia, 447, 448; Sc. plumieri, 5, 17, 
86, 92, 227-236, 242, 277-283, 288, 
291, 446, 447, 451-454 

Scandinavia; West Indian seed-drift, 
21, 23, 25, 27, 35, 78, 81, 122, 146, 
153, 162, 173, 208; stranded bottle- 
drift, 52, 53, 65, 495 

Scharff, R. F., 331, 460, 497 ; similarity 
in the structure of the Bermudas and 
the Bahamas, 273; origin of the Ber- 
mudian flora and fauna, 466; on the 
North polar area as a dispersion-centre, 
325 

Schimper, A. F. W., 294; Indo-Malayan 
strand plants, 141, 157, 167, 192, 229, 
458 ; littoral plants of tropical America, 
143, 156, 203, 204, 447; buoyancy of 
seeds and fruits and dispersal by cur- 
rents, 93, 116, 156, 203, 207, 225, 231, 
234, 242, 248; foliage of Juniperus 
nana, 431, 432 

Schjoth, A., West Indian seed-drift on 
European beaches, 20, 44 

Schmidt, J. A., on plants of the Cape 
Verde Islands, 155, 167, 170, 488 

Schott, G., on bottle-drifts and their 
indications in the Atlantic, Indian, 
and Pacific Oceans; Atlantic, 46-82; 
Southern, Indian, and Pacific Oceans, 
294-312; data relating to particular 
regions and localities and utilised in 
the Notes of the Appendix as given 
in the list on page 441, viz. on the 
Equatorial Atlantic Currents, Azores, 
Bermudas, Canaries, Madeira, Turks 
Group, etc.; derelicts, 472, 473 



GENERAL INDEX 



527 



Schulz, on Cakile, 185 

" Schwan," s.s., bottle-drift, 475 

Scilly Islands; sea-fans, 22; capture of 

a Leathery Turtle, 41. 
Scirpus, 417; S. constrictus, 455; S. 

fluitans and S. multicaulis, 371, 378, 

380, 381, 387, 403, 420; S. palustris, 

381, 403, 420; S. plantagineus, 105, 
455; S. savii, 378, 403 

Scitaminese, 315 
Scleria, 455 

Scotland and the Hebrides; stranded 

West Indian seeds, 22-27, 31, 122; 

bottle-drift stranded, 49, 52, 53, 65, 

68. See also Hebrides. 
Sea-apple (Manicaria saccifera), 127 
Sea-bean (Entada scandens), 21, 22 
Sea-birds, as seed-dispersers. See Birds, 

Gulls, Petrels, Frigate-birds, Boobies. 
Sea-coconut (Manicaria saccifera), 127 
Sea Finns, West Indian drift seeds, 25 
Sea -nut, West Indian drift seeds, 22 
Sea-side grape, Coccoloba uvifera, q. v. 
Securinega buxifolia, 434 
Seeds; falling rates, 354, 355, 422-425, 

439; mucosity, 419, 421, 427; hypo- 

cotylar, 213, 214, 243 
Seemann, B., Dioclea panamensis, 132; 

Acacia farnesiana, 171; Thespesia 

populnea, 246; Ximenia americana, 

253 

Selaginellae, 375 

Selala, the seedless Rhizophora of Fiji, 
99, 110 

Sempervivum, in the Canaries, 408, and 

Madeira, 410 
Senecio, capacity for dispersal by winds, 

425, 439 
Sequoia, 318, 327 
Serapias, 377 

Sernander, R., West Indian seeds and 
fruits on the Scandinavian coast, 21, 
36, 37, 42, 44, 122, 146, 153, 173 
dispersal of Juniperus communis, 430 ; 

Sesuvium, 101, 279, 280, 290; S. portula- 
castrum, 278-281, 288, 291, 451-454, 
477 

Sete Cidades, Azores, 394, 396 
Seubert, M. ; on the flora of the Azores, 
359, 362, 363, 368-370, 385, 389, 392, 
428-438, 440 ; zones of vegetation on 
Pico, 368; reliability of the altitudes, 
362, 363, 425 
Seven-year apple. See Genipa clusii- 
folia, 210 

Seven-year vine, Ipomcea tuberosa, 210 
Seward, A. C, on the Glossopteris flora, 
328, 331 

Shaler, Prof., submarine springs off 

Florida coast, 497 
Sherardia arvensis, 491 
Shetland Islands; West Indian seeds 

stranded, 22, 24, 27, 34, 122; also 



turtles and drift-wood, 40-42 ; stranded 
bottle-drift, 52, 53, 65 

Shreve, Forrest, the forests of eastern 
Jamaica, 156, 243 

Sibbald, Sir R., West Indian seeds on the 
beaches of Scotland and of the islands, 
23, 31, 33, 44 

Sibthorpia, 420 ; S. europea in the Azores, 
371, 375, 383, 387, 402, 420 , 436; on 
its fitness for dispersal, 419, 422 

Sicyos angulatus, 294 

Sideroxylon, in Hawaii, 489 ; S. mermu- 
lana, in Madeira, 410 

Sierra Leone; bottle-drift from the 
vicinity of St. Paul's Rocks, 50, 59, 
475, and from off the north coast of 
Brazil, 59, 476 

Silene maritima ; in Iceland, 187 ; in the 
Azores, 384, 388, 404, 421; capacity 
for dispersal by currents and sea-birds, 
418, 421 

Silver Bank, 255, 258, 264 

" Sir Edward Hawke," King's Schooner, 
265, 489 

Skye, Isle of ; bottle-drift, 68 

Sloane, Sir H. ; West Indian seeds on the 
Irish and Scottish coasts and on the 
Hebrides and the Orkneys, 21-24, 30- 
34, 41, 44, 122, 128, 136, 137. Re- 
marks on some Jamaican plants, 
Spondias lutea, 111, 113; Hippomane 
mancinella, 115; Mammea americana, 
144; Crescentia cujete, 147; Cassia 
fistula, 152, 155; Sapindus saponaria, 
157; Grias cauliflora, 211; Guilan- 
dina, 457. References to the drift 
fruits of Manicaria saccifera, 128, etc., 
Sacoglottis amazonica, 136, 137, and 
Ipomoea tuberosa, 161-163, the prickles 
of Zanthoxylum, 164, and the sea-fans 
of the Scilly Islands, 22 

Smilax; in the Azores, 369, 376, 380, 
392, 401; in the Canaries, 401, 406, 
408 ; modes of dispersal, 417, 418 

Smith, Lea, stranded alligator in the 
Turks Islands, 487 

Snakes, transported by currents to islands, 
Keeling Atoll, St. Vincent, Turks 
Islands, 303, 486, 487 

Snuff-boxes, seeds of Entada scandens 
from European beaches thus used, 25, 
33 

Soap-berry. See Sapindus saponaria. 
Solan Goose, Molucca beans found in its 

nest, 31 
Solanum pseudo-capsicum, 491 
Solidago sempervirens, 385, 404, 421 
Solomon Islands, Dioclea reflexa, 132 
Solvent-stone, signification of old Norse 

name for the stranded seeds of Entada 

scandens, 23 
Sonchus oleraceus, capacity for dispersal 

by winds, 424, 425, 439 



528 



GENERAL INDEX 



Sophora, 133, 239 ; S. ckrysophylla, 239 ; 

S. tetraptera, 239, 294, 307, 308, 311; 

S. tomentosa, 6, 12, 87, 92, 198, 207, 

237, 244, 286, 288, 291 
Spain; stranded bottle-drift, 53, 68; 

bottles thrown overboard off the coasts, 

57, 66 

Spartium junceum, 492 
Spartocytisus nubigenus (Retama), 409, 
411 

Spergularia marina, 384, 388, 404, 418, 
421 

Sphagnum. See under Carex compared 
with Sphagnum, as indexed under 
Carex, 332-358. The principal species 
there referred to are : cymbifolium, 
349; fimbriatum, 337-339, 348, 349; 
junghuhnianum, 350; medium, 337- 
339, 348, 349; mexicanum, 337, 338; 
papillosum, 349; pappeanum, 344, 
346; plumulosum, 337, 338; pulchri- 
coma, 337, 341, 344, 346; rufescens, 
341; torreyanum, 337, 338; turgi- 
dulum, 341. 
Spirula, shells in beach-drift, 6, 38 
Spondias lutea (Hog-Plum), 4, 11-14, 

17, 87, 91, 111, 193 
Spores, falling rates of, 355, 422-425, 439 
Springs; probable sea-water springs in 
the Black River Morass, 101, 102; 
fresh-water springs in the same morass, 
104; submarine springs, 497; springs 
on Pico, 496, 497 
Spruce, R. ; Carapa guianensis, 141, 143 ; 
Grias, 212; Manicaria saccifera, 128; 
Omphalea diandra, 160; Phytelephas, 
17 

Spunk-box, origin of the Hebridean name 

for Entada scandens, 25 
Stachys arvensis, 391 
Stapf, Dr., Sacoglottis amazonica, 134, 

135 

Statice; numerous Canarian species, 

408, 448; S. bahamensis, 285, 286; 

S. limonium, 384 
Sterility and cold currents. See Climate. 
Sterpin, J., translator of the book of 

Debes on the Faroe Islands, 23 
Stewart Island, Uncinia, 498 
Storks, migrating from Europe to South 

Africa, 354 
Strom, Norwegian naturalist of the 

eighteenth century, on the tropical 

seeds in Scandinavian beach-drift, 22, 

35-37, 41, 44, 146, 153 
Suffida, 290 

Subsecunda, Sphagnum subsection, simi- 
lar behaviour in Africa and Australia, 
344, 353, 357 

Sugar-cane, early cultivation in the Azores, 
397 

Suriana maritima; general treatment, 
239; in the Turks Islands, 278-283, 



288, 289, 291; in the Florida sand- 
keys, 451, 452 ; influence of wind-pres- 
sure on its growth, 446, 447; repre- 
sented in beach seed-drift, 6, 241, 242 ; 
distribution, 85, 87, 92 

Swallows, migration from Great Britain 
to South Africa, 354 

Sweden ; stranding of West Indian seeds, 
27, 36, and bottle-drift, 52 

Swietenia mahogani, 242; its associates 
in the open forests of Jamaica and 
Cuba, 111, 112. See under Mahogany. 

Symphonia, 83, 84; S. globulifera (Hog- 
gum); general treatment, 243; de- 
tails, 3, 15, 16, 83, 86, 88, 90-92, 95, 
159, 205 

Syngonium, 16 

Tabernaemontanus, 44, 45 
Tamarind, 155 

Tamujo (Tamucho), name in Azores of 

Myrsine africana, 434 
Tansley, A. G., Sphagnum tussocks, 377 
Taxus baccata (Teixo), in the Azores, 

369, 370, 380, 386, 387, 392, 393, 401, 

405, 406, 417, 418, 436 
Taylor, N., plants of Grand Turk, 286, 

287 

Teneriffe; flora and zones of vegetation 
compared with those of Pico (Azores) 
and Madeira, 406-411, 415; summit 
plants, 411 ; shore plants, 448 ; Sphag- 
num, 344, 346 ; ascending air-currents, 
425; climate compared with that of 
Pico and Madeira, 409; angle of the 
mountain's slope, 366; Dragon-tree, 
487; beach-drift, 38 ; bottle-drift from 
Greenland waters, 484, 496 

Terceira; Santa Barbara ascent, 383, 
387; original forests, 393; buried 
Junipers, 395 

Terminalia, 83, 84, 116, 175, 204, 231; 
T. katappa, 6, 11, 116 

Tetragonia expansa, in Azores, 385 

Texas, the chaparral scrub, 167-169, 
229; bottle-drift stranded, 58. See 
under Mexico, Gulf of, for other 
data. 

Thespesia, 83, 326; T. populnea, general 
treatment, 244 ; compared with Acacia 
farnesiana and Hibiscus tiliaceus, 172; 
seeds and capsules in beach-drift, 5, 
6, 12; references to station, etc., 87, 
92, 116, 168, 194, 197, 200, 287, 288, 
291 ; T. danis, 246 

Thomson, A. L., migration of storks, 354 

Thrinax, 109, 287 

Thuret, G., floating capacities of seeds, 
447 

Thymus serpyllum, var. angustifolius of 
the Azores, 370-373, 376, 377, 383, 
386, 387, 402, 407, 411; concerning 
its dispersal, 417, 419, 422 



GENERAL INDEX 



529 



Tierra del Fuego. See Fuegia and Cape 
Horn. 

" Tilbury," H.M.S., long drift of mast, 40 
Tilia, 326 

Tillandsia, tumble-weed in Peru, 271, 
493 

Tillinghast, W. H., on old maps of the 
Bahamas, 264, 276 

"Times"; capture of a Leathery Turtle 
off Stilly, ~ 41; bottle-drift in the 
Southern Ocean, 49, 300 

Tobago; beach-drift, 6, 13, 121, 129; 
beach-trees, 245 ; stranded bottle-drift, 
60, 61, 73, 75 

Toland, J., marginal notes in a copy of 
Martin's book on the Hebrides, 43 

Tornlinson, seed of Entada scandens on 
the Irish coast, 31 

Tonning, West Indian seeds on Scandi- 
navian coasts, 22, 23, 35, 37, 44, 146, 
153, 208, 209 

Tournefortia, 248; T. argentea, 247- 
251, 453, 454; T. sarmentosa, 248 

i gnaphalodes; general treatment, 

247-251; in the Turks Islands, 202, 
278-283, 288, 291, 292 ; on the Florida 
sand-keys, 451-454; distribution and 
dispersal, 87, 88, 93, 95, 228; repre- 
sented in beach-drift, 6, 242; influence 
of wind -pressure on growth, 446, 
447 

Tree-Euphorbias. See Euphorbia sty- 
giana. 

Tree-Heaths. See Erica arborea and E. 

azorica. 
Tree-Lobelias, 321 

Trelease, W., on the Azorean flora, 364, 
385, 440; proportion of indigenous 
plants, 389, 391; re-discovery of 
Isoetes, 429; on Campanula vidalii, 
427; on other plants, 185, 359, 362, 
389, 392, 431, 433-438, 491, 492 

Treub, M., the re-stocking of Rrakatau 
with plants, 116, 142, 154; experiments 
at Buitenzorg on Scsevola kcenigii, 
234, and Tournefortia argentea, 249 

Trichomanes speciosum, in Azores, 375, 
379 

Trif olium, 390 ; T. arvense, 492 

Trinidad Island (West Indies); beach- 
drift, 6, 13, 121, 129, 130, 131, 136, 
143 ; as a centre for receiving and dis- 
tributing seed-drift, 74, 81 ; the home 
of Manicaria saccifera, 129, and Saco- 
glottis amazonica, 133-136; stranded 
bottle-drift, 60, 61, 67, 70, 73, 74, 75, 
80, 442^45, 474, 475 

Tristan da Cunha; stranded seeds of 
Dioclea reflexa, 132; the habitat of 
Uncinia, 498-501 

Tristram, H. B., on a north polar centre 
of dispersion, 325 

Tropaeolaceae, 314, 316 
M M 



Trovisco, Azorean name of Daphne 

laureola, 428 
Tschudi, J. J. von, on the medanos or 

moving sand-hills of Peru, 270, 271, 

494 

Tulloch, J., West Indian seeds from the 

Shetland coasts, 34, 131 
Tumble-weed, in sandy plains of Peru, 

271, 493 

Tunis, stranding of bottle-drift from the 

Atlantic, 53 
Turk's-head cactus. See Melocactus com- 
munis. 
Turks Islands : 

Bottle - drift ; stranded on the islands, 
49, 54-57, 58, 64, 462-465; bottles 
dropped overboard in the vicinity 
of the islands, 465, 477 ; connection 
with Bermuda, 470 
Iguanas, alligators, and snakes, 486 
Stranded seed-drift ; suitability of the 
islands for the study of oceanic seed- 
drift in transit, 2, 8, 14, 19; list of 
plants supplying the foreign seed- 
drift, 10, 11; the materials of the 
local seed-drift, 446 
The flora ; general description, 277- 
293 ; the separate islands, Pear Cay, 

278, Penniston Cay, 278, Long Cay, 

279, Gibb Cay, 280, Eastern Cay, 280, 
Round Cay, 281, Greater Sand Cay, 
281, Cotton Cay, 282, Salt Cay, 283, 
289, Grand Turk, 283-290 ; dispersal 
agencies, 290; influence of wind- 
pressure on plant-growth, 446. 

The geology and general characters, 
254-276. See summary of results on 
p. 273. 

Turtles, carried by the currents from West 

Indian waters to north-west Europe, 

40, 42, 48, 78 
Typha ; in Jamaica, 15, 105-107 ; 

capacity for dispersal by winds, 423 

424, 439 

Ubussu palm (Manicaria saccifera), 128 
"Die, E., Sphagnum in South Brazil, 
353 

Umbelliferae, unidentified shore plant of 

Teneriffe, 448 
Uncinia, 294, 358, 498-501 ; dispersal by 

birds, 337, 500; U. compacta, 498; 

U. brevicaulis, 498; U. jamaicensis, 

500 ; U. kingii, 501 ; U. macrolepis, 

498, 501 

Underground waters, soakage seaward in 

volcanic islands, 497 
Uniola paniculata, 85, 280, 282, 291, 451, 

453 

United States Hydrographic Office, charts 
of bottle-drift tracks in the North 
Atlantic, 47, 54, 66, 75, 82, 466-471,, 
etc. See under J. Page. 



530 



GENERAL INDEX 



Urban, L, references to West Indian 
plants in his Symbolge Antillanse, 92, 
128, 134, 144-148, 181, 184, 217, 220, 
226, 244, 250, 426, 455-457 

Utricularia, in Jamaica, 16, 104, 105, 107 

Vaccinium; in the Canaries, 406, 408; 
in Madeira, 407, 410; dispersal by- 
birds, 418; V. cylindraceum, in the 
Azores, 369, 370, 374, 375, 380, 382, 
383, 386, 392, 401, 437 

Vaughan, T. W. ; on the formation of 
the Western Bahamas, 254, 276, 504 ; 
the seolian rocks of the Bahamas and 
Bermudas compared, 273, 502 ; ocean- 
holes, 258, 503. A bulky volume by 
this author on reef-corals and their 
associated phenomena is now (October 
1916) being published by the Carnegie 
Institution of Washington. 

Vegetable-Ivory palm (Phytelephas), 17 

Velellse, washed up on the south coast of 
England, 29 

Venezuela; bottle-drift brought by the 
Main Equatorial Current, 60, 61, 73, 75 

Verbascum, in Azores, 375 

Verbena officinalis, 491 

Vette Nyre (Fairy kidneys), old Norse 
name for the stranded seeds of Entada 
scandens, 23, 25 

Vibe, A., West Indian seed-drift in Scan- 
dinavia, 20, 36, 41, 44 

Viburnum; in the Canaries, 405, 406, 
408, 438; mode of dispersal, 418; V. 
tinus, in the Azores, 360, 369, 375, 
376, 382, 386, 392, 401, 405, 437 

Vicia sativa, 492 

Vidal, Captain; survey of the Azores, 
365, 366; discoverer of Campanula 
vidalii, 427 

Vigna, 252 ; V. lutea, 250, 252 ; V. luteola, 
6, 87, 92, 250 

Vinca rosea, 290 

Viola; palustris, 371, 377, 387, 402; 

paradoxa, 411 ; teydensis, 411 
Virgin Islands, shore plants, 116, 244, 

457 

Mary's Nut, Hebridean name of 

stranded West Indian seeds, 24 
Visnea, 412 

Vogel, Dr., on the shore vegetation of 
African west coast, 159, 194, 207 

Wahlenberg, G., West Indian seeds 
stranded in northern Scandinavia, 35, 
36, 44 

Wales, stranding of West Indian seeds 
and fruits, 26, 30 

Walker, W. F., on the Azores, 440; the 
original forests and the trees buried in 
volcanic ashes, 393-397, 437; "sar- 
gasso " weed washed up on the islands, 
485; the Madeitan juniper, 410 



Wallace, A. R., the Azorean flora from 
the standpoint of dispersal, 390, 413, 
440 ; dispersal of seeds by winds, 422, 
439; plant-stocking of Bermuda, 466; 
survival of ancient groups of plants, 318 
Wallace, Rev. J.,\onWest Indian seeds, 
Wallace, Dr. J., J etc., thrown up on 
the Orkney Islands, 22, 23, 33, 40, 41, 
44, 131, 161-163 
Waltershausen, S. von, on West Indian 
seeds and drift-timber stranded on 
Iceland, 20, 35, 41, 45 
Warde, Mrs. H. B., 238 
Warming, E., 45 ; seeds blown across the 
Cattegat, 425; foliage of Juniperus 
nana and J. communis, 431, 432 
Warnstorf, C, Sphagnacese, 332-358, 
411, 440 ; the connections of the Azorean 
Sphagna, 478 
Warren, Miss U. ; seeds of Entada scan- 
dens on the north coast of Cornwall, 45 
Water-hyacinth. See Pontederia. 
Watkins, F. H., on the first salt -rakers 
and the original condition of the Turks 
Islands, 184, 276, 277, 487 
Watson, H. C, on the Azorean flora, 359, 
362, 385, 394, 440 ; the total number 
of plants and the introduced element, 
389-391; the vertical distribution of 
Hochstetter and Seubert criticised, 
362, 363, 425 ; summit plants of Pico, 
370; aquatic plants, 378; character 
and composition of the original forests, 
391-393 ; beach plants of Porto Pym, 
384 ; Campanula vidalii and the Maca- 
ronesian Campanulas, 427, 428; dis- 
covery of Isoetes azorica, 429, and 
Littorella lacustris, 432; the Azorean 
Juniper, 431 ; other references to plants 
218, 364, 371, 434-436, 438, 492; the 
snow on Pico, 372 
Webb, P. B., on Dracaena draco in 

Madeira, 487 
Webster, J. W., on the Yew of Pico, 397, 
437, 440 

Weeds, their significance, 391, 493 
Wells of Pico, 497 

Welwitsch, on Acacia farnesiana in the 
Cape Verde Islands, 170 

West Australian Current; influence on 
the climate, 272; its probable role in 
seed dispersal, 301 

Indies; West Indian and West 

African strand-floras compared, 83- 
95; West Indian seeds on European 
beaches, 20-45; bottle-drift from the 
West Indies to Europe, 52, and from 
Europe to the West Indies, 57. See 
the summary on p. 78 for a guide to 
the general bottle-drift results for the 
West Indies, also under Bahamas, 
Caribbean Sea, Greater and Lesser 
Antilles. 



GENERAL INDEX 



531 



Westmoreland Morass (Jamaica), vegeta- 
tion, 16, 106 

West- Wind Drift Current and the indica- 
tions of bottle-drift, 60, 295-300, 305- 
312 

White. Dr., on the source of the flora of 

St. Helena, 460 
Sea, West Indian seed-drift on its 

shores, 36, 78 
Whymper, ascending air-currents on the 

Andes, 425 
Wiegmann's Archiv fur Naturgeschichte, 

362, 368, 425 
Wight, Isle of; stranding of a West 

Indian seed, 28 
Wilkes, Captain, bottle-drift in the 

Southern Ocean, 49, 300 
Willdenow, on the West Indian home of 

Acacia farnesiana, 167, 168 
" William Torr," wrecked in Davis 

Strait ; drift of casks, 50 
Wilser, L., on the north polar centre of 

dispersal, 325 
Wind; dispersal of seeds and spores, 

354, 422-425, 439; seeds of the maho- 
gany tree carried by the wind, 243; 

ascending air-currents on mountains 

as seed and spore carriers, 425, 439; 

effects of wind-pressure on shrubs in 

the Turks Islands, 446. 
" W. L. White," derelict schooner, drifted 

across the North Atlantic, 472 
Woad (Isatis tinctoria), early cultivation 

in the Azores. 397 



Woodwardia; W. radicans, 370, 375; 

W. virginica, 378 
Worm, O., an old Danish naturalist; on 

Scandinavian tropical seed-drift, 21, 

35, 45 

Wortley, E. J., on Hymensea courbaril 
in Jamaica, 140 

Xerophily and a littoral station, 228, 229, 
238, 239. For further references see 
Littoral plants (c); and for a discus- 
sion of xerophily as a product of later 
geological ages, due to the progressive 
differentiation of climate, see p. 319. 

Ximenia, 83, 253 ; X. americana, 87, 92, 
252 

Yew, in the Azores, 397, 437. See Taxus 
baccata. 

Yucatan, bottle-drift stranded, 53, 466. 

See Central America, Honduras, 

Nicaragua. 
Strait, traversed by drift brought 

by the equatorial currents, 58, 70-72 
Yuccas, 168 

Zanthoxylum, prickles in beach-drift, 
164 

Zaragoza mangrove (Conocarpus erectus), 
201 

Zeleny, J., on the falling rates of spores, 
423 

Zingiberacese, 315 

Zygophyllum, in the Canaries, 448, 449 



Additional Note on St. Helena. — Through an oversight, reference has not been 
made on p. 460 to the record by Burchell and Melliss of the frequent stranding of 
seeds of Entada scandens and Guilandina bonducella on the windward or southern 
coasts of this island (Chall. Bot. iii, 80; iv, 300, 302). The indications of the 
currents are that these seeds are most probably derived through the agency of the 
South Atlantic Connecting Current from Brazil, though a possible source from the 
East African coast around the Cape cannot be ignored. 



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